What will come in place of the question mark (?) to complete the series logically? Q 2, R 3, S 5, T 7, U 11, ?

Refer to the following number series and answer the question. (Left) 2 8 9 3 5 7 6 3 1 4 8 9 3 5 1 5 6 2 1 4 7 5 2 3 8 2 9 (Right) How many such odd digits are there, each of which is immediately preceded by an odd digit and also immediately followed by an even digit?

Which of the following letter-number clusters will replace the question mark (?) in the given series to make it logically complete? CAR78, GEV86, KIZ94, OMD102, ?