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 choices:
A) 1/122
B) 1/129
C) 1/121
D) 1/128
E) 1/126
Out of nine, five are good and four are defective. Required probability   = 4C4/9C4   = 1/126   Answer: 1/126
<result>E</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?