The answer is 105 because 180 - 75 = 105, which is the measure of angle 7. and 7 is a corresponding angle to 3, therefore angle 3 = 105. The reason the answer is not b is because angles 2 and 4 have a angle measure of 75, and 3 and 1 have a angle measure of 105.
I am pretty sure I am correct, tell me if I am wrong.
