Question #N484

The following sentence contains an error in punctuation: "Because of the high-pitched sounds that flycatchers produce, they have developed an exceptional sense of hearing."

Which choice corrects the error in the sentence above?
A. Because, of the high-pitched sounds that flycatchers produce they have developed an exceptional sense of hearing.
B. Because of the high-pitched sounds that flycatchers produce, they have developed an exceptional sense of hearing.
C. Because of the high-pitched sounds that flycatchers produce; they have developed an exceptional sense of hearing.
D. Because of the high-pitched sounds that flycatchers produce, they, have developed an exceptional sense of hearing.