Question

given that it is cheaper and more ____ ocean transportation, rather than air or roadway portage, carries the most commercial cargo worldwide. which choice completes the text so that it conforms to the conventions of standard english? choose 1 answer: a efficient, so b efficient so c efficient, d efficient

Explanation:

1. The first part needs an adjective to parallel "cheaper" to describe ocean transportation, so "efficient" is required here.
2. The two independent clauses "it is cheaper and more efficient" and "ocean transportation... carries the most commercial cargo worldwide" need a comma plus the coordinating conjunction "so" to connect them properly in Standard English.

Answer:

A. efficient, so