### Instruction: A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that all the four bulbs are defective.
Answer Choices: (A) 1/166 (B) 1/129 (C) 1/526 (D) 1/121 (E) 1/126.### Response: Let's think about the multi-choice question.
Out of nine, five are good and four are defective. Required probability = 4C4/9C4 = 1/126.The answer is E