The answers are b) and c) (break middle
and (continue outer);
Ronnie is right about a) - this will break out of the outer loop completely.
b) is correct because when y is 10, break middle; is called so therefore, it jumps back to the outer loop, thus incrementing x by 1. (so the middle loop goes through 10 iterations, then x is x + 1 - all the way up to 99).
c) is correct for the same reason as b
d) is not correct. (continue middle; seems to make an infinite loop).