In following number series, two terms have been put within brackets. Choose the appropriate option - Which number replace question mark in the series 7, 12, 19, ?, 39.

Answer: B. 28

Clearly, the given sequence follows the pattern:
+5, +7, +9 ...  i.e., 7 + 5 = 12,  12 + 7 = 19, ... .
.'. Missing Number = 19 + 9 = 28.
Hence, the answer is (b).