Answer:
A. 4.5
Explanation:
You can find the center value (median) either by crossing off a box from the lower number end and one off the higher number end until you find the middle value, or by writing them out and doing the same.
2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 8, 9, 10
Since there are 20 numbers, there are two center numbers, 4 and 5. So we take the average of them, which is 4.5