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.	Choose the correct choice from the following options
A) 1/126 B) 1/127 C) 1/26 D) 1/129 E) 1/261
Out of nine, five are good and four are defective.   Required probability = â´Câ‚„/â¹Câ‚„ = 1/126   1/126nswer: 1/126
<result>A</result>
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.