Alright so this is the one Trophy in this game that I myself could not figure out on my own.
This occurs towards the end of case 2: Spectrum, at some point one of the guys will talk to you about giving you a quiz. MAKE SURE TO SAVE AT THIS MOMENT, then go ahead and take the quiz. Below are the answers to the quiz
ABCAAAACCA
BABCAAABAA
BABABBABAA
BCABBAACBA
BBBBBAABCA
CBBBAAAAAA
BBCCAAABBA
CBCAAAABCA
AABCAAAABA
AABAAAAAAA
We can all thank HeavenSmile51 over at Game FAQ's for this one. If you wish to know the actual answer and not just the the letter you can check out his post below
https://www.gamefaqs.com/boards/200321-the-silver-case/75284...