Sorry Guys, Angle 12 & 10 are effectively corresponding angles, but angle 10 & 7 are alternate interior angles. Anyways, Angle 12 & 10 are congruent and 10 & 7 are congruent. At the end, the three angles 12, 10, and 7 have the same measure. If we put it otherwise, the line B is intersecting line D which form right angles equals to 90 degrees, so angle 12 = 90, and the same happens with angle 10 and 7, so the three angles are congruent, but at the same time, angle 7 is supplementary with angle 12 because their sum is equal to 180, (90 + 90 = 180). If you think from different angles is hard to choose the right answer, so what I guess is that we don't need to take into account the angle 10, just the fact that line A intersect line C, and Line B intersect line D forming right angles, and that angle 7 and 12 are right angles which sum equals 180, therefore, we could say that they are supplementary angles, but also congruent because they measure the same, so at the end, I don't know what answer to choose. Both seems correct to me.