Answer:
i
Step-by-step explanation:
There has to be a mod 26 operation for c, since the alphabet only has 26 letters.
But otherwise
[tex]c = E(p+k) = p + 9 \mod{26}[/tex]
p is the initial position of the letter. So for example, a = 0, b = 1, c = 2, q = 16, z = 25...
9 is by how much the encrypted character will change relative to the original.
We want to cipher the letter q.
So p = 25.
[tex]c = E(p+k) = p + 9 \mod{26}[/tex]
[tex]c = 25 + 9 \mod{26}[/tex]
[tex]c = 34 \mod{26}[/tex]
The remainder of 34 divided by 26 is 8.
So
[tex]c = 8[/tex]
Which means that q is encrypted as 'i'.
