The options are:
a)35°
b)45°
d)65°
(i did not include c)55° because i already took the quiz and that option is incorrect)
. so much for your time.

Starting with that supplementary angles, or angles that combine to form a straight line, equal 180 degrees, we can note that angle GDE = 180-angle BDE.
Next, since complimentary angles, or angles that form a right angle, add up to 90 degrees, we get that 90-angle GDE = angle GDF. Therefore, by substituting values in, we get that angle GDE=180-125=55 degrees. Next, 90-55=35 degrees, which is your answer.

Feel free to ask further questions!