निम्नलिखित चार संख्या-युग्मों में से तीन एक निश्चित पैटर्न का पालन करते हैं और इस प्रकार एक समूह बनाते हैं। कौन सा युग्म उस समूह से संबंधित नहीं है?

Choose the pair that is different from the other pairs based on a specific logic.

Based on alphabetical order, three of the following four letter-clusters are alike in a certain way and thus form a group. Which is the one that does not belong to that group? (Note: The odd man out is not based on the number of consonants/vowels or their position in the letter cluster)