Step 1: Understanding the Concept:
This question requires knowledge of specific luxury room classifications in the hospitality industry.
Step 2: Detailed Explanation:
A Pent House is considered the most premium offering in a hotel. Its defining feature is its location on the highest floor, often utilizing the roof/terrace space. The "open to the sky" feature refers to private patios or terraces that come as part of the suite, offering panoramic views.
Step 3: Final Answer:
Mr. Sharma should book a Pent House to get a top-floor room with sky access.