Identify Which Revision of the Following Sentence Is Correct

Identify which revision of the following sentence is correct:
Each of the girls thought that they would be named Miss Mid-South.

A) Each of the girls thought that she would be named Miss Mid-South.
B) Each of the girls thought that he or she would be named Miss Mid-South.
C) Either A or B can be correct depending on the intended meaning of the sentence.
D) Neither A nor B is correct.