【单选题】

For any 3 given numbers, which of the following is always equivalent to adding the 3 numbers together and then dividing the sum by 3

Ⅰ. Ordering the 3 numbers numerically, from highest to lowest, and then selecting the middle number.
Ⅱ.Dividing each of the numbers by 3 and then adding the results together.
Ⅲ. Multiplying each number by 6, adding the resulting products together, and then dividing the sum by 9.
A、Ⅰ only
B、Ⅱ only
C、Ⅰ and Ⅱ only
D、Ⅱ and Ⅲ only
E、None of the above