Parallel lines s and t are cut by a transversal r.

Parallel lines s and t are cut by transversal r. Clockwise from top left, the angles formed by lines r and s are 1, 2, 3, 4; formed by lines r and t are 5, 6, 7, 8.

Which angles are alternate interior angles?
Angle3 and Angle5
Angle1 and Angle7
Angle3 and Angle7
Angle4 and Angle5