In "IDTMS," what does "T" stand

Which letter-cluster will replace the question mark (?) in the following series?

CED, FJH, KQN, (?) , AKF

The position of how many letters will remain unchanged if each of the letter in the word 'BACHELOR' is arranged in alphabetical order?

44 : 4 :: 287 : 7 :: ? : 10

Select the set in which the numbers are related in the same way as are the numbers of the following sets.

Consider the given paragraph and decide which of the given assumptions in the options is implicit in the paragraph.

Select the correct mirror image of the given figure when the mirror is placed at LM as shown below.

Statements: 

Some tomatoes are potato.

All carrots are potato.

All potatoes are onion

Conclusions:

In the following question, select the related letter pair from the given alternatives. 

ER : ET :: ?