The number of four-digit numbers strictly greater than 4321 that can be formed using the digits 0, 1, 2, 3, 4, 5 (repetition of digits is allowed) is:

Correct option is D. 310
(1) The number of four-digit numbers starting with 5 is equal to 6³=216
(2) Starting with 44 and 55 is equal to 36 × 2 = 72
(3) Starting with 433, 434 and 435 is equal to 6 × 3 = 18
(4) Remaining numbers are 4322, 4323, 4324, 4325 is equal to 4
so total number are 216 + 72 + 18 + 4 = 310