Explanation:

- The series given is: 46, 51, 61, 84, 121, 201.

- Let’s examine the differences between consecutive numbers:

- Difference between 46 and 51 is 5.

- Difference between 51 and 61 is 10.

- Difference between 61 and 84 is 23.

- Difference between 84 and 121 is 37.

- Difference between 121 and 201 is 80.

- The differences don’t form any consistent pattern or series.

- When analyzing individual numbers, the number '84' doesn’t fit naturally into a logical sequence or pattern of differences.

- The correct sequence actually suggests progressive increments resembling Fibonacci numbers, but inconsistent implementation, indicating '84' is misplaced.

- 84 appears to be the wrong number in the series.