Three of the following four letter-clusters are alike in a certain way and one is different. Pick the odd one out.

From the given option,

$$J \ \underrightarrow{+1} \ K \ \underrightarrow{+2} \ N \ \underrightarrow{+3} \ R \ \underrightarrow{+3} \ C$$

Apart from the first option, rest of all are following the same pattern.

$$P \ \underrightarrow{+1} \ Q \ \underrightarrow{+2} \ T  \ \underrightarrow{+3} \ X \ \underrightarrow{+4} \ C$$

$$G \ \underrightarrow{+1} \ H \ \underrightarrow{+2} \ K \ \underrightarrow{+3} \ O \ \underrightarrow{+4} \ T$$

$$U \ \underrightarrow{+1} \ V \ \underrightarrow{+2} \ Y \ \underrightarrow{+3} \ C \ \underrightarrow{+4} \ H$$