Find the wrong number in the given series.
20, 40, 200, 400, 2000, 4000, 8000.

Information Given:
Series: 20, 40, 200, 400, 2000, 4000, 8000

Pattern: ×2, ×5 alternately

Step-by-step:
20 × 2 = 40 ✔
40 × 5 = 200 ✔
200 × 2 = 400 ✔
400 × 5 = 2000 ✔
2000 × 2 = 4000 ✔
4000 × 5 = 20000 (should be, not 8000) ❌

Final Answer:
8000

Final Correct Option:
A