Correct option is B
Given
Series: 1, 50, 100, 5000, 10000
Formula / Concept used
The pattern alternates multiplication by 50 and 2.
Solution
1 × 50 = 50, 50 × 2 = 100, 100 × 50 = 5000, 5000 × 2 = 10000, 10000 × 50 = 500000
The correct option is (b)