Analogy - Verbal and Reasoning

Directions to SolveIn each word of the following questions consists of pair of words bearing a relationship among these, from amongst the alternatives, pick up the pair that best illustrate a similar relationship.
Q1:

Rectangle : Pentagon

A Side : Angle

B Diagonal : Perimeter

C Triangle : Rectangle

D Circle : Square

ANS:C - Triangle : Rectangle

Explanation: Second one had one more side than the first.