If sec^2(x) – 1 = sin(x) , which one of the following is a possible value for x?

how do you do this?

Thanks in advance. I don't get the sin,cosine rules so please help.! =)

The choices are

a) -$\displaystyle \frac{\pi}{2}$

b)=$\displaystyle \frac{\pi}{4}$

c) 0

d) $\displaystyle \frac{\pi}{2}$

e) $\displaystyle \frac{\pi}{4}$

thanks in advance!