Final answer:
The opportunity cost to a pharmacist who drives a taxi is the income that could be earned by working as a pharmacist instead of driving a taxi.
Step-by-step explanation:
The opportunity cost to a pharmacist who drives a taxi would be the income that could be earned by working as a pharmacist instead of driving a taxi.
Opportunity cost refers to what one must give up to obtain what they desire, and in this case, the pharmacist would be giving up their salary from the pharmacy job by choosing to drive a taxi instead. The other options mentioned, such as fuel cost and time spent driving, may be considered expenses or factors to consider, but they do not represent the true opportunity cost.