Man doesn't live . . . . . . . . bread only.

Answer: Option B

The correct preposition is "on" because the idiomatic expression is "live on", which means to survive or exist by consuming a particular type of food or source of nourishment.

The sentence "Man doesn't live on bread only." means that human beings need more than just food to live a meaningful and fulfilling life. It is a well-known expression derived from a biblical quotation.

Examples:

She lives on fruits and vegetables.

Many animals live on grass.