Few of the letters are given followed by a question mark (?) these letters are following a specific pattern you have to give the correct option which can replace question mark.
Find the next letter in the series: C, D, B, E, ?
Show answer & explanation
Correct answer: C
Explanation
Series for odd terms (1st, 3rd, 5th...): C (+2)
B (+2)
Subtracting 1 from C gives B.
Similarly, subtracting 1 from B gives the blank (A).
Series for even terms (2nd, 4th...): D (+1) 
E (+1) 
J
D is the fourth letter in the alphabet and E is the fifth.
This sequence continues for even terms and reaches the 10th letter, 'J' (D E J).
Therefore, the appropriate option in place of the question mark (?) would be J.