Answer:
C (and D ?????)
Explanation:
the difference of 1 and 2 is 1.
of 2 and 5 it is 3.
of 5 and 10 it is 5.
of 10 and 17 it is 7.
of 17 and 26 it is 9.
so, the driving sequence is
1, 3, 5, 7, 9
the next number here is 11, so that the next number in the pattern is
26 + 11 = 37