A box contains twelve bulbs out of which seven are defective. If seven bulbs are chosen at random, find the probability that all the four bulbs are defective?	Select the correct option
A) 1/127
B) 1/792
C) 1/789
D) 1/689
E) 1/126
Out of twelve, five are good and seven are defective. Required probability   = 7C7/12C7   = 1/792   Answer: 1/792
<result>B</result>
A box contains twelve bulbs out of which seven are defective. If seven bulbs are chosen at random, find the probability that all the four bulbs are defective?