Final answer:
A good reservoir rock for oil extraction must have both high porosity to store the oil and high permeability to allow the oil to be pumped out efficiently. An impermeable caprock is also important to prevent the oil from escaping.
Step-by-step explanation:
To answer the question regarding what makes a rock a good reservoir rock for oil extraction, we must understand the importance of both porosity and permeability.
Porosity refers to the amount of open space within a rock, which can store fluids such as oil. However, porosity alone does not ensure that oil can be easily extracted. The rock must also have high permeability, which is the ability for a fluid to flow through the rock's interconnected spaces or pores.
Therefore, the correct answer to the question is:
a) high permeability and porosity
This is because a reservoir rock must allow the storage of oil (high porosity) and also enable it to be pumped out efficiently (high permeability). Moreover, an impermeable caprock structure is necessary to sit atop the permeable and porous rock to prevent the oil from escaping.