En el club de fotografía, fotografía como fotografos. a. mas b. menos c. tantos d. tantas

D. Tantas

Explanation:

I'll suppose you meant to write "fotógrafas" (female photographers) instead of "fotografía" (photo), because that would make much more sense.

En el club de fotografía, hay _TANTAS__ fotógrafas como fotógrafos.

(In the photo club, there are as many female photographers as male photographers)

We're dealing with a comparison here, the most common forms of comparison are when one quantity is lower/higher than another, then we use "más... que"/"menos... que" ("more/less... than") or when two quantities are equal then we use "tanto... como"/"tan... como" ("as many... as").  

In the case of "tanto", it has to be modified to match the name it refers to (in this case 'fotógrafas", feminine plural, 'tanto' becomes 'tantas').