Which option has the longest delivery time when sending the approved budget?

The choice indicating local mail as having the longest delivery time is based on typical postal service operations. Local mail is generally designed for lower priority items and typically goes through several processing stages, which can extend delivery times, especially compared to other options like aeroplane or courier services that are priority-focused.

When considering the various methods:

• Sending by aeroplane typically ensures rapid delivery, given its speed and logistics involved in air transport.
• Using a courier service is specifically aimed at timely, efficient deliveries and often guarantees faster arrival than standard postal services.
• Hand delivery via train may seem slower due to the mode of transport, but it often falls under dedicated delivery arrangements that can expedite the process.

In contrast, local mail is often subject to batching, routing, and potential delays, making it the slowest option for sending an approved budget. This is aligned with the common experiences individuals have with effective postal system timelines, where regular mail may take days longer than quicker delivery methods.