Explanation:

- The passage describes a scene at the Varagaliar elephant camp in the Anamalai Tiger Reserve during the evening. It describes the activities happening at the location.

- For blank No. (4), the words surrounding it suggest that a group of people associated with the Forest Department are present.

- Option 1: "person" - This is singular and doesn't fit well with "half-a-dozen."

- Option 2: "employee" - Also singular and less appropriate as it’s specific to general employment, not necessarily government or organizational context.

- Option 3: "ministers" - Implies high-ranking political positions, usually inappropriate for daily activities at a camp.

- Option 4: "officials" - This is plural, matches the context, and implies people in authoritative positions, fitting well with "Forest Department."