Question

form a compound sentence.
_________________________ many americans bike to work.
a large number of europeans and
according to this magazine article,
with gasoline so expensive,
gasoline can be expensive, so

Explanation:

To form a compound sentence, we need a clause that can connect with "many Americans bike to work" using a conjunction. The option "Gasoline can be expensive, so" provides a cause - effect relationship (gasoline being expensive leads to Americans biking to work) and the "so" is a conjunction for compound sentences. The other options: "A large number of Europeans and" is an incomplete phrase, "According to this magazine article," is a prepositional phrase, and "With gasoline so expensive," is a prepositional phrase, not a clause that forms a compound sentence.

Answer:

Gasoline can be expensive, so