A
B
C
D
Explanation
Correct answer: B.
Choice B is correct. It's given that two lines intersect at a point. The angles with measures of and are vertical angles, so it follows that they are equal in measure. Therefore, . If , it follows that .
Why the other choices are wrong
Choice A
Choice A is incorrect. This is the measure, in degrees, of the complement of an angle with a measure of , not the value of .
Choice C
Choice C is incorrect and may result from conceptual or calculation errors.
Choice D
Choice D is incorrect and may result from conceptual or calculation errors.