Answer: I would say B, and here's why I believe so
Explanation: D would be incorrect since it doesn't make sense in this context, and by that logic, neither does A, so we can mentally throw those out of the playing field.
This leaves us with B and C, which I do believe C very well could be the answer as well since it would make sense, but I personally would go with B. Denying someone their rights is a social inequality, and the LGBT community in general is still considered un-equal to their heterosexual counterparts in MANY ways, example: in some states, gay couples aren't allowed to adopt. and in some countries, gay marriage isn't even legal yet! (isn't that unfair?!) To add more backstory, religion has also been used to deny the rights of women in the older days, (see "sexism in the early 1900's")