Answer:
C. a || b, COnverse of the Alternate Interior Angles theorem
Step-by-step explanation:
TD;LR - ∠7 and ∠9 are on the interior sides of the lines a and b = converse Alternate Interior angles theorem
oIf you were to look at it using the lines c and d, like I did when I first saw this, it gets confusing and you can come to the conclusion it can't be exterior or interior because one is interior and the other exterior, so in order for this to make sense you have to look at it using a and b as the lines and c and d as the transitive lines. Knowing transitive property and how transitive lines work we come to the conclusion that ∠7 and ∠9 are interior angles for lines a and b letting us know it has to do with the Alternate interior angles theorem. This allows us to cross Options A and B off the list giving you a 50/50 chance of getting it right if you were to guess, but since we know that the angles are interior we can conclude that we did have enough information to figure it out, therefore C is the right answer and D is incorrect