Correct Response: A. Cracking is a process used to break up the complex long-chain hydrocarbon molecules found in crude oil and produce simpler short-chain hydrocarbon molecules, thereby yielding lighter oils such as diesel fuel and gasoline. Impurities (B), such as sulfur and nitrogen, are removed using a process called hydrotreating. Crude oil must first undergo a distillation process where it is separated into different products such as tar (C) and naphtha. Naphtha is used to make plastics (C). A quality assay (D) is an evaluation of the chemical makeup of a particular crude oil in order to determine its compatibility with a particular refinery and to check for possible environmental or other problems.
