I’ve tried the values 25, 50, 11, and 3. All are wrong. I’m down to my last two responses and am asking for any help.
2 Answers

ml will depend on the value of l which in turn depends on n.
So, for n=5 the possible values of l are 0, 1, 2, 3, 4. (corresponding to s, p, d, f, g)
For each value of l, ml will go from l to +l or as follows:
l = 0 ml = 0 (1 value)
l = 1 ml = 1 0 +1 (3 values)
l = 2 ml = 2 1 0 +1 +2 (5 values)
l = 3 ml = 3 2 1 0 +1 +2 +3 (7 values)
l=4 ml = (9 values)
Total values = 1 + 3 + 5 + 7 + 9 = 25 possible values of ml, so it looks like your first guess was correct.
Unless they mean that the different values range from 5 to zero, then the answer would be 11, but that was also one of your guesses.
Strange question indeed.

l = n – 1
So, for n = 5, that means l = 4
Values of ml vary from l to +l, which means there are 9 possible values