Answer:
A, C, D
Explanation:
When lines are parallel, alternate interior angles at a transversal (5 & 6) are congruent, as are corresponding angles (2 & 3), (2 & 4). The converse is also true: congruent angles mean the lines are parallel.
Angles 2 & 3 are corresponding angles at the transversal r if lines p and q are parallel, so their congruence will guarantee that those lines are parallel. (choice A)
Angles 2 & 4 are corresponding angles at the transversal q if lines r and s are parallel, so their congruence will guarantee that those lines are parallel. (choice C)
Angles 5 & 6 are alternate interior angles at the transversal p if lines r and s are parallel, so their congruence will guarantee that those lines are parallel. (choice D)
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Angles 5 and 7 have no common side, so their congruence does not guarantee anything about the lines that create them. Choice B is not applicable.