Answer:
The answer is A.
Explanation:
The example given in the question represents a variable cost. Variable cost can be defined as a cost that changes according to the level of output that is produced. In this case, according to the times the ski lift is used during the week. If the ski lift is used 40 times, than each will be $2, if it is used 20 times, each will be $4. So the correct answer is option A.
I hope this answer helps.