Which of these might affect how an age-of-consent law is interpreted in different states? a. the location of the sexual activity b. the genders of the participants c. whether one party is a teacher or other trusted adult d. whether both parties consented to the activity

The laws determining the age of consent typically already specify the age and gender - so gender should not be left to interpretation. 

Similarly, we can exclude the option of "consent" since this is what this law is about generally - whether the person is old enough to consent. 

the location also should not play a role. 

The best answer seems to be that  if C.  one party is a teacher or other trusted adult, the age of consent can be higher - because the younger person has to be protected from the abuse of power by that person. 

So that you don't get baby's but also prevents stis such as hiv