Let's investigate each choice and do a process of elimination. A vacation pay is a salary that you can still get even when you are not working and away from work. This could be a clause from your contract agreement with your company. This could be a piece rate because a tour guide receives money based on the amount of work done. Salary is more of a monthly pay. Lastly, this is not an hourly pay because it is note based on the amount of time in work.
Thus, the answer is B.