Given the series: 5, 6, 8, 14, 38, 158, ...
The differences are: 1, 2, 6, 24, 120.
Observing the pattern in the differences, each term is multiplied by an increasing integer:
Following this pattern, the next difference should be:
120 × 6 = 720
Adding this difference to the last term in the series:
158 + 720 = 878
The next number in the series is 878 (Option D).