Answer:
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').
