Which Letter Replaces the ? mark

Question

Answer 1

Answer is "O" as each letter is first letter of the consecutive number.

1. One
2. Two
3. Three
4. Four
5. Five
   ...
   ...

Answer 2

its O

one=O
two=T
three=T
four=F
............................
.............

Answer 3

E

as 1st and 3rd row are same & 2nd and 4th row are same.
So, E will replace ?

Answer 4

Which Letter Replaces the ? mark Read
Ans is - E