If KNIFE is coded as MPKHG, then what does the code DTGCF stand for ?

In the following series, one letter is missing as shown by the question mark (?). Select the missing letter from the given options.
E,J,O,T,?

Consider the given question and decide which of the following statements is sufficient to
answer the question.
How long will X take to build the wall?
Statements:
1. X and Y together can build the wall in 8 days.
2. X takes 5 days more than Y to build the wall.

School W in a village, provides education from nursery to standard 4. In the same village, School B and school K provide education from standard 5 to 10. School F, which is in a nearby town, provides higher secondary education, that is, standard $$11^{th}$$ and $$12^{th}$$ only. The village has only three schools. Parents in the village have requested for more schools to the local panchayat.
Which conclusion follows the given statements?

If pointing to Mr. X, Ms. Y said that Mr. X’s wife is the only daughter of Ms. Y’s father,
then Ms. Y is Mr. X’s .........