Select the most appropriate one-word substitution for the given group of words.
One who studies God and religion

Correct option is B

The correct one-word for the given group of words is (b) theologian.
Theologian: One who studies God and religion.
Meanings of other options:
• Theorist: a person who develops abstract models or theories.
• Atheist: a person who does not believe in the existence of a god or gods.
• Theist: a person who believes in the existence of a god or gods.