Which letter-cluster will replace the question mark (?) to complete the given series?

MU, NE, PX, QF, SA, TG, ?

Four clusters have been given out of which three are alike in some manner and one is different. Select the one that is different.

Option

Select the set in which the numbers are related in the same way as are the numbers of the following sets. (NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E. g. 13 – Operations on 13 such as adding / subtracting / multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed)

(9, 16, 5)
(7, 9, 4)

In a certain code language, 'ABROAD' is written as 'DFORDH' and ‘ACCESS’ is written as ‘DGECVW’. How will 'AGENCY' be written in that language?

Which letter-cluster will replace the question mark (?) to complete the given series?

ABCD, FVJV, KPQN, PJXF, ?

By interchanging the given two signs and numbers which of the following equation will be correct?
 + and –, 7 and 6

In a certain code language, ‘TECHNOLOGY’ is written as ‘NHCETOLOGY’, ‘GENERATION’ is written as ‘RENEGATION’. How will ‘APOCALYPSE’ be written in that language?

Select the odd group of numbers. (NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g.13 – Operations on 13 such as adding /subtracting /multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed)

Option