Which of these is an example of how the media might perpetuate a sexual stereotype? a) a heterosexual male seeks relationships with heterosexual females. b) an asexual female seeks out and maintains a committed relationship with asexual man c) a homosexual male expresses himself with a female gender identity. d) a hetersexual female expresses herself with a male gender identity

I think we can easily rule out B and D. Asexual means you don't find any sex attractive, meaning you wouldn't seek any relationships. And, a heterosexual female never really expresses herself as a male, usually that's what a lesbian would do.

Leaving A, and C.

But, I think A is rather a fact that a stereotype, and not all homosexual men express them self with female gender, but it's a stereotype, so I'd go with C.  

The answer you're looking for is C) a homosexual male expresses himself with a female gender identity.