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?	Pick one:	A) 1/129	B) 1/124	C) 1/128	D) 1/139	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>
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?