For which of the following lists of numbers is the mode equal to the average (arithmetic mean) ?
(A)10, 10, 10, 50, 70 (B)10, 20, 25, 30, 40 (C)15, 35, 35, 35, 55 (D)10, 20, 25, 35, 45 (E)5, 15, 25, 25, 50
C