Two men dressed as police officers stole about $200 million worth of art from the Isabella Stewart Gardner Museum early this morning. The two burglars knocked on a side door of the museum at about 1:15 am. They told the two security guards on duty that there was a disturbance in the area. The guards then made the very serious mistake of allowing the two men to go into the building. After they went in, the two burglars tied the guards up with tape. The two men stole 11 paintings and an ancient Chinese vase. The stolen works included three paintings by Rembrandt. A maintenance worker discovered the two guards at about 7 am and called police. One of the greatest losses was Rembrandt's works, "The Storm on the Sea of Galilee." It was a very popular attraction at the museum and was one of the most valuable works stolen. Museum officials said that the value of the stolen art is at least 200 million dollars, and may in fact be much more. The true value of the paintings is unknown, because they have not been on the market for nearly a century. This is considered to be the biggest theft ever in the United States. Officials are waiting to see whether the burglars will or try to sell them to a private collector. Museum officials and police are not sure why the burglars chose certain works and not others. There are other paintings in the museum that are even more valuable than the ones that were stolen. Special investigators are looking into the theft and the museum's security system. They believe that this is a "professional job," because the people involved were well prepared and knew what they wanted. The investigators believe that this is a "professional job" because the burglars    _    .
were dressed as police officers didn't steal the most valuable works liked Rembrandt's work and made careful plans about the theft made careful plans about the theft
Question: Two men dressed as police officers stole about $200 million worth of art from the Isabella Stewart Gardner Museum early this morning. The two burglars knocked on a side door of the museum at about 1:15 am. They told the two security guards on duty that there was a disturbance in the area. The guards then made the very serious mistake of allowing the two men to go into the building. After they went in, the two burglars tied the guards up with tape. The two men stole 11 paintings and an ancient Chinese vase. The stolen works included three paintings by Rembrandt. A maintenance worker discovered the two guards at about 7 am and called police. One of the greatest losses was Rembrandt's works, "The Storm on the Sea of Galilee." It was a very popular attraction at the museum and was one of the most valuable works stolen. Museum officials said that the value of the stolen art is at least 200 million dollars, and may in fact be much more. The true value of the paintings is unknown, because they have not been on the market for nearly a century. This is considered to be the biggest theft ever in the United States. Officials are waiting to see whether the burglars will or try to sell them to a private collector. Museum officials and police are not sure why the burglars chose certain works and not others. There are other paintings in the museum that are even more valuable than the ones that were stolen. Special investigators are looking into the theft and the museum's security system. They believe that this is a "professional job," because the people involved were well prepared and knew what they wanted. The investigators believe that this is a "professional job" because the burglars    _    .
A. were dressed as police officers
B. didn't steal the most valuable works
C. liked Rembrandt's work and made careful plans about the theft
D. made careful plans about the theft
Answer: