SAT数学真题The least and greatest numbers in a list of 7real num

SAT数学真题
The least and greatest numbers in a list of 7
real numbers are 2 and 20,respectively.The median of the list is 6,and the
number 3 occurs most often in the list.Which of the following could be the
average (arithmetic mean) of the numbers in the list?
I.7 II.8.5 III.10
A.I only B.I and II only C.I and III only D.II and III only E.I,II and III