Find limit of x approaching pi/4 of (sin (x) - sin (pi/4))/(x-pi/4)

a. pi
b. square root of 2
c. square root of 3 over 2
d. square root of 2 over 2
e. 1/2

Calculus help please.

Using L'Hopitals, we can see that this limit is equivalent to:

lim x-> pi/4 cos(x) = cos(pi/4) = √2/2

Choose D

I got the square root of 2 over 2.
The same as 1/sqrt 2