Jefferson's Department Store typically sells over a third of all its merchandise in November and December. Management has found that it must hire workers during this period of increased business to supplement its permanent employees

the answer is "contingent workers"

Explanation:

contingent workers are in a way, temporary workers that are hired during the seasonal times to make it possible for the company to accommodate the excess demand and customer requirements during the period.  

these workers are not permanent and the company can let them go after the seasonal period is over.

one of the appeals of a sole proprietorship is that business expenses are kept separate from your personal income tax return