Explanation:

- For 4 friends (A, B, C, D) in a line:

- “A and B are ahead of at least 1 person.” ? So, A and B cannot be last; they can be 1st, 2nd, or 3rd.

- “B stands between C and D.” ? The order must be C-B-D or D-B-C.

- “D does not stand last.” ? So D can’t be in the 4th position.

Let’s deduce possible orders:

- Since D can’t be last, and B must be between C and D, B can’t be 1st or 4th.

- Main possibility: C-B-D-A or A-C-B-D.

- But A must be ahead of at least one person, so A cannot be last.

- In C-B-D-A, B is between C and D, D is not last. D is 3rd, not 4th—good. But A is last, which violates the “A ahead of at least 1 person” rule.

- Try A-C-B-D:

- A is 1st, C is 2nd, B 3rd, D 4th. B is between C and D, and A is ahead of three people. But D is last, which violates the “D not last” rule.

Try C-D-B-A:

- B is between D and C, but D is 2nd, B 3rd, A is last (again, A cannot be last).

Try D-C-B-A:

- B is between C and A—not valid, since B must be between C and D.

Try A-B-D-C:

- B is between A and D, but must be between C and D.

Try B-C-D-A:

- B between C and D, D not last (D is 3rd). A is last, so violates rule for A.

Try B-D-C-A:

- B between D and C, D not last. A is last (again, violates rule for A).

Try B-D-A-C or B-C-A-D may also be checked but both break given conditions.

Only possibility left:

D-A-B-C

- A and B ahead of at least one person (A is 2nd, B is 3rd), B is between A and C (not between C and D, so invalid).

Hence, among these, only A stands first is possible without violating any rule.

Option 1: A