दी गई संख्या श्रृंखला में से विषम (odd one out) संख्या ज्ञात कीजिए: 3, 7, 11, 15, 19, 22

Four letter-pairs are given below. The letters on the left side of (-) are related to the letters on the right side following a specific logic/rule. Three of them share the same rule. Select the odd one out.

Four letter-pairs are given. The letters on the left side of (-) are related to the letters on the right side of (-) by some logic. Three of them follow the same logic. Select the odd one out.