Question #N1272

The group of children is excited to visit the museum; they have been studying the history of the United States for weeks.

Which of the following revisions to the sentence above is the most effective way to combine the sentences?
A. The group of children is excited to visit the museum, they have been studying the history of the United States for weeks.
B. The group of children is excited to visit the museum and they have been studying the history of the United States for weeks.
C. The group of children is excited to visit the museum, having been studying the history of the United States for weeks.
D. The group of children is excited to visit the museum because they have been studying the history of the United States for weeks.