An example for a vector quantity is-

Correct option is B

The correct Ans is (b) Momentum

Explanation:
A vector quantity is defined as a quantity that has both magnitude and direction. Among the given options:

• Momentum is a vector quantity because it depends on both the magnitude of the mass and velocity (which has direction).
  Formula: Momentum (p) = mass (m) × velocity (v)
  Since velocity is a vector quantity, momentum also has direction.

Other Options Analysis:

• Length (Option a): It is a scalar quantity as it only has magnitude and no direction.
• Speed (Option c): It is a scalar quantity as it measures the rate of distance traveled but lacks direction.
• Distance (Option d): It is also a scalar quantity because it only measures how far an object has traveled, irrespective of direction.

Key Points:

• Scalar quantities have only magnitude (e.g., length, speed, distance).
• Vector quantities have both magnitude and direction (e.g., velocity, force, momentum).