B is the correct answer.
A is not the correct answer because sexual health is influenced by multiple factors at any given moment. It is never just one of those factors.
C is not the correct answer because many different fields, such as biology, medicine, biochemistry, neuroscience, evolutionary anthropologists, cultural anthropologists and many more fields can contribute greatly to our understanding of sexual health.
D is not correct because all of those factors contribute to different degrees of sexual health depending on the person, and depending on the context. To say that any of those factors are more of an influence than another is inaccurate: you start to fall dangerously close to either biological determinism or cultural determinism (commonly known as "nature vs nurture"). We know any form of determinism is not accurate, based on evolutionary studies and many other experiments from several different fields.
Hope this helps!
