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 answer:	A) 1/125	B) 1/117	C) 1/198	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.