A3. The number of ternary numbers whose sum of digits is equal to 5 is:
(A) 12
(B) 13
(C) 14
(D) 15
(E) 16
A3. Fifteen three-digit numbers have the sum of their digits equal to 5. These numbers are: 500, 401, 410, 104, 140, 311, 131, 113, 221, 212, 122, 320, 302, 230, 203.