The odd one out is $\boxed{\text{D}}$.
The other three options, $\text{A}$, $\text{B}$, and $\text{C}$, all have the same pattern: the first two letters are the same, and the third letter is one letter after the second letter. For example, in $\text{HJN}$, the first two letters are both “H”, and the third letter is “J”, which is one letter after “H”. In $\text{JLP}$, the first two letters are both “J”, and the third letter is “L”, which is one letter after “J”. In $\text{PRU}$, the first two letters are both “P”, and the third letter is “R”, which is one letter after “P”.
However, in $\text{QSW}$, the first two letters are “Q” and “S”, and the third letter is “W”, which is two letters after “S”. This does not follow the same pattern as the other three options.