Answer: -pi/4 and 3pi/4
Explanation:
Whenever you're given an inverse trig function like this, think "tangent of what gives me -1?" There are multiple ways in which you can solve this; knowing how tangent work, guess checking sin/cos to get -1, or using a calculator. The only way tangent can be an integer is if the sine and cosine of the angle are equal.
The only spots on the pi circle where this happens is pi/4, 3pi/4, 5pi/4, and 7pi/4. Answers B and D are correct