A customer forgets a foru-digit code for an Automatic Teller Machine (ATM) in a bank. However, he remembers that this code consists of digits 3,5,6 and 9. Find the largest possible nuim,ber of trials necessary to obtain the correct code.

An old man while dialing a 7-digit telephone number remembers that the first four digits consist of one 1's, one 2's and two 3's. he also remembers that the fifth digit is either a 4 or 5 while has no memory of the sixt digit, he remembers that the seventh digit is 9 minus the sixth digit, maximum number of distinct trials he has to try to make sure that he dials the correct telephone number, is A. 360 B. 240 C. 216 D. none of these