Final answer:
The proportion of light hydrocarbons in petroleum is approximately 25%.
Step-by-step explanation:
The proportion of light hydrocarbons in petroleum can vary, but typically, it is approximately 25%.
According to the given references, light hydrocarbons such as methane, ethane, propane, and butane make up a significant portion of petroleum, usually in gaseous or liquid form. In Figure 8.4, it is mentioned that still gases and light liquids account for a considerable amount of petroleum.
Therefore, option b) Approximately 25% is the most accurate choice.