Select the Letter of the Sentence That Uses the Semicolon

Select the letter of the sentence that uses the semicolon correctly.
-_____

A) Although some people do not realize it; dolphins are intelligent; the navy trains them for underwater work.
B) Although some people do not realize it; dolphins are intelligent. The navy trains them for underwater work.
C) Although some people do not realize it, dolphins are intelligent; the navy trains them for underwater work.