To answer this question, we need to consider what we know about the angles ∠a and ∠b.
There is no information given on the measurements or the nature of ∠a and ∠b, Hence, we cannot find a specific relationship between these two angles.
Vertical angles are formed when two lines intersect. We don't know if ∠a and ∠b are formed by intersecting lines, So it isn't correct to choose Choice A.
Complementary angles add up to 90°, and Supplementary angles add up to 180°. As we do not know any measures or any other information about ∠a and ∠b, we cannot say that these angles are complementary or supplementary. So, Choices B and C are also not valid.
Therefore, the correct answer is (Choice D) 'None of the above'. We can not yet determine the relationship between these two angles because we lack the appropriate information about ∠a and ∠b.