A box contains 24 electric bulbs, out of which 4 are defective. Two bulbs are chosen at random from this box. The probability that at least one of these is defective is	Select the correct option:
A) 4 / 19
B) 7 / 19
C) 12 / 19
D) 24 / 77
E) none

Rationale: "solution p ( none is defective ) = 20 c 2 / 24 c 2 = 53 / 77 . p ( at least one is defective ) = ( 1 - 53 / 77 ) = 24 / 77 . answer d"
Answer: D