Answer: d. highly elastic
Step-by-step explanation:
Elasticity is a measure of the responsiveness of quantity demanded to a change in price. An elastic good for instance, will see its quantity demand drop if its price increases.
In the above scenario, when one gas station increases prices, less people demand their fuel. The reverse is true. This therefore means that the demand for both of their stations is highly elastic because them changing prices hugely affects the number of people that will come to patronise them.