O
Q
R
S
Answer is Right!
Answer is Wrong!
The correct answer is $\boxed{\text{R}}$.
The sequence is a list of letters that are two places apart in the alphabet. The first letter is $\text{H}$, which is two places before $\text{I}$. The second letter is $\text{I}$, which is two places before $\text{K}$. The third letter is $\text{K}$, which is two places before $\text{N}$. The fourth letter is $\text{N}$, which is two places before $\text{R}$.
The other options are incorrect because they are not two places before the letters in the sequence.