Several organizations have defined intermodalism differently. Within the CITT, which of the following descriptions best describes the practice of intermodalism?

Question $1$Select one:

a$.$

A shipment that travels over multiple modes of transport.

b$.$

A shipment with one common $($through$)$ bill of lading traveling over multiple modes of transport.

c$.$

A shipment that travels in one freight carrying unit over multiple modes of transport.

d$.$

A shipment that travels with multiple carriers within the same mode of transportation.