Walking along, Tintin overhead the two island gate guards, Thomas and Thompson chatting amongst themselves.
Thomson : He told us we have consecutive letters on our papers
Thompson : Yeah he told me too.
Thomson : I don't know what your letter is.
Thompson : Neither do I know your letter.
Thomson : Now I know. Tintin listened this conversation and wondered what the two letters could be. When he was about to leave the island, Thomson stopped him and told him to say the password, which were the two letters. Maximum of how many attempts does Tintin need to make to have the correct pair of letters, and thus pass successfully?

Options

A. 1
B. 2
C. 4
D. More than 4

Explanation

1.     Thomson : He told us we have consecutive letters on our papers  2.     Thompson : Yeah he told me too.  3.     Thomson : I don't know what your letter is.  4.     Thompson : Neither do I know your letter.  5.     Thomson : Now I know.  From 3, we can infer that Thomson’s letter is not A/Z.  From 4, we can infer that Thompson’s letter is also not A/Z.  Had Thomson’s letter been B/Y, then Thompson’s letter will become C/X from the  Excerpt 3,4&5.  Had Thomson’s letter been C/X, then, from 3&4, we understand that Thompson’s  letter cannot be B/Y as, then, statement 4 will be false (as then Thompson will  realise that Thomson’s letter is C, as A is not possible from 3). Hence, for 1&4 to be  true, Thompson’s letter had to be D/W.  For any other letter combination, there is no conclusive answer.  The Combination therefore is, BC/CD/YX/XW  Hence the answer is option: C)4 tries