Which of the following is an estimated time en route option?

The estimated time en route (ETE) for a flight refers to the projected duration it will take to complete a journey from the departure point to the destination. In this context, 1:35 represents a precise time format that translates to 1 hour and 35 minutes, which is a valid way to express ETE, encompassing hours and minutes.

Choosing a format that includes both hours and minutes provides clarity in planning and coordination, especially in aviation, where precise timekeeping is essential. This level of detail ensures that flight crews, air traffic control, and other relevant parties have an accurate understanding of how long the flight is expected to take, allowing for better planning and resource management.

The other options presented, while also expressed in hours and minutes, are not chosen in this case. However, all of them could technically serve as ETE formats, as they all adhere to the hours and minutes model, and could each represent valid time projections for a flight.