Heading: How the author returned to Delhi from Nepal

The author returned to Delhi from Nepal by plane. This option is the correct answer. Let's explore the details behind this choice.

Explanation:

The author's return journey to Delhi from Nepal was most likely by plane due to several reasons:

1. Distance: Nepal and Delhi are geographically quite far apart. The distance between the two places is around 800 kilometers. Traveling such a long distance by road, train, or water route would be time-consuming and inconvenient.

2. Time-saving: Air travel is the fastest mode of transportation when it comes to covering long distances. Taking a flight from Nepal to Delhi would significantly reduce the travel time compared to other means of transport. This is particularly important when the author wants to reach Delhi quickly.

3. Connectivity: Both Nepal and Delhi have well-established international airports. There are regular flights connecting the two destinations, making air travel a convenient option. These flights provide good connectivity and a wide range of options for travelers.

4. Comfort: Air travel offers a higher level of comfort compared to other modes of transportation. Passengers can relax in comfortable seats, enjoy in-flight services, and experience a smooth and hassle-free journey. This is especially beneficial for long-distance travel.

5. Safety: Air travel is generally considered to be one of the safest modes of transportation. Airlines have strict safety protocols in place, including regular maintenance checks, trained pilots, and advanced navigation systems. This ensures a secure journey for passengers.

In conclusion, considering the distance, time-saving aspect, connectivity, comfort, and safety, it is evident that the author's return journey from Nepal to Delhi was most likely by plane.