Explanation:

Let's evaluate the statements:

- Statement A:

- 20% of the number is one-fifth of the number.

- Both 20% of a number and one-fifth of a number mean the same thing mathematically (0.20 of the number), so this statement doesn't provide enough information to determine a specific number.

- Statement B:

- 5/6th of the number is less than that number by 15.

- This translates to: Original number - (5/6 × Original number) = 15.

- This equation can be simplified to find the specific number.

- Analysis of Options:

- (a): Statement A alone is insufficient, so this isn't correct.

- (b): Statement B alone provides a solvable equation to find the number.

- (c): Both A and B together are not needed, as B alone is sufficient.

- (d): Both statements individually are not sufficient, but B alone is sufficient.

Correct Answer: Option 2 (b)