For an angle to have the exact same value for sine and cosine, it has to be located in a quadrant where both sine and cosine have the same sign. Those quadrants are 1 and 3. In quadrant 1, both sine and cosine are positive, and in quadrant 3 both sine and cosine are negative.
In quadrants 2 and 4, there are angles where sine and cosine could have the same magnitude, but not the same sign.
Therefore, correct answer is C.
