E.
Because:
If you look at it carefully, the first one, b, +1 equals the third one, c.
So basically B+1=C, A+1=B, C+1=D, B+1=C, D+1=E, C+1=D, E+1=F, D+1=.....E!!!
So yeah.
The question is stated wrong.It should be: "What is the next letter in the series O T T F F ?", and the answer is " S ".These are the initial letters of the words: One Two Three Four Five, followed by Six.
d
It looks as if every third letter is an "r"; the remaining letters are in sequence.
E. They are the initial letters of the numbers 0-7 in words: Zero, One, Two, Seven The next is 8 - Eight
oNe, tWo, tHree, fOur,fIve,sIx etc. It is the second letter of each consecutive number
This looks like two series interspered with each other. Let's put some letters in upper-case and others in lower-case BaCbDcEdF... so the next letter would be the lower-case 'e'
what is the next letter e h l q
X
S
c
Q
The next (and last) letter is C. Just as a countdown counts backwards, this series is "countdown" spelled backwards.
c is next
y
S
T
It's the letter D of course! Haven't you heard of Jason D?!