The last combination (3,2,3,+1/2) is not allowed.
The quantum numbers are (n, l, ml, s)
l, the second quantum number, may take values from 0 to n - 1; so:
n = 3 => l may be 0, 1, or 2 => the first and second quantum numbers are a valid combination.
The third quantum number, ml goes from - l to +l, so, given that l is lower than 3, ml cannot be 3. That is why this is not a valid combination.
