Witch sentence uses the the dashes correctly

A: there will be alot of people at graduation - - and maybe some free food.

B: there will be - - alot of people at graduation and maybe some free food.

C: there will be alot of people - - at graduation and maybe some free food.

The correct sentence is (A).

In (A), the dash correctly adds in an additional thought: "and maybe some free food".

In (B), the dash in between "be" and "a lot" interrupts the sentence at a strange place that causes the reader to read it like there is a hiccup there.

In (C), again, like (B), the dash is in a strange places that interrupts the sentence.

Thus, the answer is (A).

The answer is A - there will be a lot of people at graduation-- - and maybe some free food.