Your Answer is

Correct Answer is B

Explanation

There are 10 dots on a circle, and Kim paints every nth dot clockwise, and finally paints all of them. If it is 2, you can paint 5 dots in each circle, and the cycle starts after one circle, and it is impossible to paint all of them. Finished, if it is 5, you can paint 2 in each circle, and the cycle will start after one circle, and you can't finish it. If it is 4, you can paint 2 in each circle, and you can start to cycle in 2 circles, and you can't finish it. If it is 6 If so, you can paint 1 in each circle, and start the cycle in 3 circles, and you can't finish painting, only 3 can. So choose B

(When the divisor and the dividend have common factors, the dots cannot be painted)