Force that slows down a Swimmer's movement in the water is known as:

Correct option is B

The correct answer is (b).
Introduction
Drag force is the resistive force opposing a swimmer's motion through water, arising from viscosity and pressure differences. It slows the swimmer down.
Information Booster

• Drag acts opposite to the direction of movement.
• Caused by friction and form (pressure) drag.
• Swimmers streamline to reduce drag.
• Buoyancy helps float; gravity pulls down; drafting is a technique to reduce drag.

• Buoyancy is upward, not a slowing force.
• Gravity acts downward, not necessarily slowing forward motion.
• Drafting is a strategy, not the force itself.