To what would you compare the transport layer?

The above question has multiple choices as below

A. Data links
B. The post office
C. Driving a car
D. A train

The answer is (B) The Post Office.

In layman’s terms, transport layer is similar to the post office functions of delivering parcels and letters at the agreed delivery deadlines. It also notices any dropped info and re-transmits it.
Just like the post office, the transport layer directs messages and information between specific end users. If by mistake you write a letter to the wrong person, the letter will be returned and the postal employee will stamp it as address unknown.

Iwould go with either b or c, not sure which one.