11) Frugal: Parsimonious :: ?
Frugal and parsimonious are synonyms of each other as they both have the same meaning 'being stingy'. Similarly, in the four pairs, only option D pair has the words with same meaning or synonyms of each other.
12) Paw: Cat :: Hoof: ?
The foot of cat is known as paw, and the foot of a horse is known as a hoof.
13) Race: Fatigue :: Fast: ?
Race causes fatigue and fast causes hunger.
14) Water: Pitcher :: ? : Vase
A pitcher is used to store water and a vase is used to display cut flowers.
15) December: ? :: May: Summer
May is the month of the summer season. December is the month of the winter season.