3 letters have to be put into their 3 respective envelopes. If the letters are inserted randomly into the envelopes, what is the probability that all the letters go into their respective envelopes? Choose the correct choice from the following answers:
A) 1/30	B) 1/6	C) 1/120	D) 1/240	E) 3/5
A-B-C-D-E (envelopes)   a-b-c-d-e (letters)   3 letters (a, b, c, d, and e) can be assigned to 3 envelopes (arranged) in 3! ways, out of which only one will be correct, thus the probability is 1/3! = 1/6.   Answer: 1/6.
<result>B</result>
3 letters have to be put into their 3 respective envelopes. If the letters are inserted randomly into the envelopes, what is the probability that all the letters go into their respective envelopes?