The artist Grandma Moses became famous for her simple, bright, cheerful paintings of American farm life.Her full name was Anna Mary Robertson Moses.But she was known to everyone as Grandma Moses because she did not begin to paint seriously until in her seventies. Born on a farm in New York, Anna had little schooling.Her days were filled with farm chores.But she often found time to make pictures.Soon, however, she became too busy to draw or paint.At the age of 12, she went to work as a servant for a family nearby.She worked for other people for many years.Then, when she was 27, she married Thomas Moses, a farmer.And they began raising a family of their own. Anna Moses could no longer do heavy farm work with age.Then, in her seventies, she began to paint in oils.Her pictures showed things she recalled from childhood-farm scenes, ice-skating, bringing home the Christmas tree.Later, she began to display her art at county fairs.Her pictures recorded a way of life that was quickly passing away.People everywhere loved these happy scenes, and soon her paintings were shown in art galleries.Grandma Moses became famous partially on account of her age, but mainly because her approach to art was modest and simple compared to many other painters of her time.Without formal training or even knowledge of Modernism, she relied on her own simple techniques to create her landscapes and scenes.She continued to paint almost until her death, on December 13, 1961 , at the age of 101. The themes in her paintings provided the comfort of a rural life that many busy Americans treasured from their past.The threat of nuclear arms that appeared on television screens and in magazines had Americans starving for something more.Grandma Moses' art appealed to those who had lost hope for the future.Her classic paintings still appear on TV commercials, greeting cards, and magazine and book covers. The key reason for her success is   _  .
her old age her plain style her lack of training her modern knowledge
Question: The artist Grandma Moses became famous for her simple, bright, cheerful paintings of American farm life.Her full name was Anna Mary Robertson Moses.But she was known to everyone as Grandma Moses because she did not begin to paint seriously until in her seventies. Born on a farm in New York, Anna had little schooling.Her days were filled with farm chores.But she often found time to make pictures.Soon, however, she became too busy to draw or paint.At the age of 12, she went to work as a servant for a family nearby.She worked for other people for many years.Then, when she was 27, she married Thomas Moses, a farmer.And they began raising a family of their own. Anna Moses could no longer do heavy farm work with age.Then, in her seventies, she began to paint in oils.Her pictures showed things she recalled from childhood-farm scenes, ice-skating, bringing home the Christmas tree.Later, she began to display her art at county fairs.Her pictures recorded a way of life that was quickly passing away.People everywhere loved these happy scenes, and soon her paintings were shown in art galleries.Grandma Moses became famous partially on account of her age, but mainly because her approach to art was modest and simple compared to many other painters of her time.Without formal training or even knowledge of Modernism, she relied on her own simple techniques to create her landscapes and scenes.She continued to paint almost until her death, on December 13, 1961 , at the age of 101. The themes in her paintings provided the comfort of a rural life that many busy Americans treasured from their past.The threat of nuclear arms that appeared on television screens and in magazines had Americans starving for something more.Grandma Moses' art appealed to those who had lost hope for the future.Her classic paintings still appear on TV commercials, greeting cards, and magazine and book covers. The key reason for her success is   _  .
A. her old age
B. her plain style
C. her lack of training
D. her modern knowledge
Answer: