Question

diluent, often ______ or condensate, is used to dilute heavy oil to help it move through pipelines.

naphtha
detritus
adrenaline
paradigm

Explanation:

Naphtha is a hydrocarbon - rich liquid often used as a diluent for heavy oil to reduce its viscosity and facilitate pipeline transportation. Detritus refers to waste or debris, adrenaline is a hormone, and paradigm is a set of concepts or a pattern.

Answer:

A. naphtha