Correct Answer:

As the number of carbon atoms in the hydrocarbon molecules increase, there is a proportional increase in the boiling point of the hydrocarbons contained in the crude oil.

The boiling point of a substance is an approximation of the energy required for a molecule to escape the intermolecular forces of attraction with its closest neighboring molecule. Generally speaking the larger the hydrocarbon molecule the greater the intermolecular forces of attraction. This is as a result of the increase in surface area of a molecule with increasing carbon count. The increased surface area of the molecule leads to greater interaction between that molecule and neighboring molecules, leading to stronger intermolecular forces.

Answering the question:

This question is based on the trends shown in the diagram. A simple way to follow a trend is by drawing a graph of the trend. This allows a visual representation of the information and usually leads to easier interpretation. In the diagram above it can already be observed that the carbon count increases as temperature increases showing the major trend immediately.