A couple is two equal, opposite, parallel forces separated by a distance, causing rotation without net translation.

Steps:

• Examine each diagram for two forces acting on the object.
• Verify if forces are equal in magnitude and opposite in direction.
• Check if forces are parallel but not collinear, ensuring a moment arm for torque.
• Confirm no net force (equal and opposite) but nonzero torque.

Why B is correct:

• Diagram B depicts two equal, opposite, parallel forces offset from each other, producing pure torque per the couple definition (τ = F × d, where d is perpendicular distance).

Why the others are wrong:

• A: Forces act in the same direction, creating net force and translation, not rotation.
• C: Forces are collinear and opposite, resulting in zero torque and possible equilibrium or translation.
• D: Forces are unequal, producing both net force and unbalanced torque.

Final answer: B