Which of the following combinations of quantum numbers (n, l, ml, ms) do not represent permissible solutions of the schrodinger equation for the electron in the hydrogen atom?
a) 9, 7, -4, 1/2
b) 8,2, 2, 1/2
c) 6, -5, -1, 1/2
d) 6, 5,-5, 1/2
e) all of the above

All of them
since hydrogen cant have n greater than 1

quantum numbers are those which tells the values of the conserved quantities of quantum system
As there are certain rules for quantum numbers one of them is that the
 l should be neccessary  be an integer between 0 and n-1
so the option  6, -5, -1, 1/2 violate this rule and doesnot obey this ruleso option C is correct for above statement
hope it helps

The answers is a nuclear changes