Either prove that KARP-LETTERS P, or prove that KARP-LETTERS is NP-complete. (Hint: Only one of these options can be completed correctly.2)

KARP-LETTERS: Instance: A list of strings of varying lengths, consisting of upper- and lower-case letters. Question: Is there a way to select a letter from each string without choosing both versions of any letter?1 KARP-LETTERS: Instance: A list of strings of varying lengths, consisting of upper- and lower-case letters. Question: Is there a way to select a letter from each string without choosing both versions of any letter?1