Find the Odd one out of the given series

6, 15, 35, 77, 165, 221

In the following question, select the odd letter/letters from the given alternatives.

In the following question, four number pairs are given. The number on left side of (–) is related to the number on the right side of (–) with some Logic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one out from the

In the following question, select the odd word pair from the given alternatives.

Four pairs of words are given below out of which three are alike in some manner and one is different. Which is different from the rest?

In the following question, select the odd letter/letters from the given alternatives.

In the following question, four number pairs are given. The number on left side of (–) is related to the number on the right side of (–) with some Logic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one out from the 

In the following question, select the odd word from the given alternatives.

In the following question, four groups of three numbers are given. In each group the second and third number are related to the first number by a Logic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one out from the given alternatives.