The following question, consist of two words each that have a certain relationship to each other, followed by four lettered pairs of words. Select the lettered pair that has the same relationship as the original pair of words: Bread : Yeast :: Curd : ?

The answer is B. Bacteria.

Bread is made by fermenting dough with yeast, which is a type of fungus. Curd is made by fermenting milk with bacteria.

A. Fungi is incorrect because fungi are not used to make curd.
C. Germs is incorrect because germs is a general term that can refer to any type of microorganism, including bacteria, viruses, and fungi.
D. Virus is incorrect because viruses are not used to make curd.