Explanation:

- The Professor has to go up to meet his IAS Officer friend, which means the Professor lives below the IAS Officer.

- The Doctor goes both up and down equally, suggesting the Doctor is in the middle flat.

- The Engineer has to go up to meet his MLA friend, meaning the Engineer is below the MLA.

- The Professor lives above the MLA, so the MLA cannot be at the top floor if the Professor must be above them.

Analyzing the options:

- Option 1: Engineer, Professor, Doctor, IAS Officer, MLA - Correct answer as all conditions match.

- Option 2: Professor, Engineer, Doctor, IAS Officer, MLA - The Engineer is below the MLA, doesn't fit.

- Option 3: IAS Officer, Engineer, Doctor, Professor, MLA - Order doesn't fit since IAS Officer should be above Professor.

- Option 4: Professor, Engineer, Doctor, MLA, IAS Officer - MLA isn't directly below the Engineer.