Question

Select the appropriate option to fill in the blank.

Unlike the most nutrients, vitamin D is a hormone and is synthesized ______ most mammals exposed to sunlight.

• A. with
• B. by
• C. for
• D. on

Answer 1

The correct option is B by

'by' is a preposition with passive agents of a sentence.

In the given statement - 'Most mammals' are the passive agents (Object);

Therefore, the correct option is: by