In which situation would combining short trips into one longer trip be most beneficial?

Combining short trips into one longer trip is particularly beneficial when fuel efficiency is a priority. This is because a vehicle typically achieves better fuel economy when maintained at a stable speed over longer distances rather than making multiple short trips. Short trips often involve frequent stops and starts, which can increase fuel consumption and emissions. Thus, by consolidating these shorter journeys into one longer trip, you minimize the number of times the vehicle has to start and stop, ultimately leading to more efficient fuel usage.

When considering other options, traveling alone or being in a hurry could lead to considerations about convenience or time efficiency rather than fuel usage. While visiting multiple cities does suggest the potential for combining travel, it does not directly relate to fuel efficiency as the primary factor meant in the context of this question. Therefore, the focus on maximizing fuel efficiency makes this option the best choice.