What is the average velocity of a particle when it returns to the starting point? Can its average speed be zero?

(N/A) Average velocity is defined as the total displacement divided by the total time taken. When a particle returns to its starting point,the total displacement is $0$. Therefore,the average velocity is $0/t = 0$.
Average speed is defined as the total distance traveled divided by the total time taken. Since distance is a scalar quantity and is always positive for a moving object,the total distance covered cannot be $0$ if the particle has moved. Thus,the average speed cannot be zero.