$A$ body can have zero average velocity but not zero average speed. Justify.

(N/A) Average velocity is defined as the ratio of total displacement to total time taken,whereas average speed is defined as the ratio of total distance travelled to total time taken.
Displacement is a vector quantity and can be zero if the initial and final positions of an object are the same (e.g.,in circular motion). Since average velocity depends on displacement,it can be zero.
Distance is a scalar quantity representing the total path length covered and is always positive for a moving body. Since average speed depends on total distance,it cannot be zero for a moving body.