It the pattern continues as ssa ssa, then 's' would be next in the sequence. This is only if the pattern is a recurring pattern. If the pattern continues without recurrence of the given sequence, then 'a' would be next, because if 's' repeats itself twice, then 'a' would also.
S
S for Saturn
E
I
F
The next letter in the sequence AAAAA is 'E'. It is a vowel sequence.
These sequence stands for: Ten Twenty Thirty Forty Fifty Sixty Seventy would be next in the sequence, so the answer is 'S'.
w
d
To provide necessary context, the original question was "What letter comes next in this sequence? WLCNIT_" Notice the first letter of each word in that question. The answer is S, corresponding to "sequence."
N for november. The sequence starts with march.
The next letter in the sequence is E. These letters form the word "HELP."