MGMAT Challenge Question - Maximize Your Score

[tstj26]

A certain game pays players in tokens, each of which is worth either m points or n points, where m and n are different positive integers whose greatest common factor is 1. In terms of m and n, what is the greatest possible sum, in points, that can be paid out with only one unique combination of these tokens? (For example, if m = 2 and n = 3, then a sum of 5 points can be created using only one combination, m + n, which is a unique combination. By contrast, a sum of 11 points can be created by 4m + n or by m + 3n. This solution does not represent a unique combination; two combinations are possible.)
(A) 2mn - 1
(B) 2mn - m - n
(C) 2mn - m - n - 1
(D) mn + m + n - 1
(E) mn - m - n

As I was going through this problem I was reading through the answer explanation. I noticed in the section that recommends picking numbers for n and m, so that n=2 and m=3, they say that answer choice A = 12.

Am I missing something here? Isn't 2(2)(3)-1=11? Or am I not properly substituting the values for n and m into the answer solutions.

I don't think this changes the answer to the question, because there are still two unique ways to get 11 from the 2s and 3s (3-3s and 1-2 OR 4-2s and 1-3). I just want to make sure I'm not missing some bigger point when it comes to substituting numbers into the answer choices.

Thanks!

[RonPurewal]

If it says 12, that's a typographical error. Thanks.

Shouldn't change the answer to the problem. (The problems are created before the answer keys.)