Marie Curie, born in Sklodovka, Poland in 1876, led a hard life as a girl. Her parents, both teachers, had small salaries and were quite poor, especially after her mother stopped teaching to raise five children and take care of her poor health. Marie's mother suffered from tuberculosis   and died of it when Marie was ten. When Marie was small, she showed great interest in science. She loved to study and hoped to become a scientist when she grew up. Her parents encouraged her interest in science. Excellent as she was in her studies, she couldn't go on with the advanced education she needed because Poland was then ruled by Russia and women were not permitted to go to college. In order to continue her education, she smoothed away many difficulties and entered Paris University. she lived a simple life and studied hard, so she graduated with the highest grades in her class. After graduation, she was engaged in scientific research in Paris University. There she met Pierre Curie, whom she married later. Pierre joined her in her research into an unknown phenomenon radiation, which a certain scientist had declared the uranium   gave off. The Curies spent several years trying their best to find the element that produced radiation. Finally they succeeded in 1902. Marie Curie won two Nobel Prizes, one for physics in 1906, together with her husband and another scientist who had also contributed to the research, the other for chemistry herself in 1911.Marie Curie was a scientist of great achievement, and the first woman ever to be honoured in the Nobel Prize history. The fact that proves Marie was the best student in her class is that   _  .
she smoothed away many difficulties and entered Paris University her grades were the highest in her class she did research work after her graduation she won the Nobel Prize finally
Question: Marie Curie, born in Sklodovka, Poland in 1876, led a hard life as a girl. Her parents, both teachers, had small salaries and were quite poor, especially after her mother stopped teaching to raise five children and take care of her poor health. Marie's mother suffered from tuberculosis   and died of it when Marie was ten. When Marie was small, she showed great interest in science. She loved to study and hoped to become a scientist when she grew up. Her parents encouraged her interest in science. Excellent as she was in her studies, she couldn't go on with the advanced education she needed because Poland was then ruled by Russia and women were not permitted to go to college. In order to continue her education, she smoothed away many difficulties and entered Paris University. she lived a simple life and studied hard, so she graduated with the highest grades in her class. After graduation, she was engaged in scientific research in Paris University. There she met Pierre Curie, whom she married later. Pierre joined her in her research into an unknown phenomenon radiation, which a certain scientist had declared the uranium   gave off. The Curies spent several years trying their best to find the element that produced radiation. Finally they succeeded in 1902. Marie Curie won two Nobel Prizes, one for physics in 1906, together with her husband and another scientist who had also contributed to the research, the other for chemistry herself in 1911.Marie Curie was a scientist of great achievement, and the first woman ever to be honoured in the Nobel Prize history. The fact that proves Marie was the best student in her class is that   _  .
A. she smoothed away many difficulties and entered Paris University
B. her grades were the highest in her class
C. she did research work after her graduation
D. she won the Nobel Prize finally
Answer: