Which of the Following Cannot Be Described by a Discrete

Which of the following cannot be described by a discrete probability distribution?

A) Sales of two medical devices in which Device A generates $35 per unit sold and will likely constitute 30% of the sales and Device B generates $50 per unit sold and will likely constitute 70% of the sales.
B) The labor cost for manufacturing goods, where one-third of the units cost $10 in labor, one-third cost $15 in labor, and one-third cost $50 in labor.
C) The cost of parts for manufacturing an item, where the parts can take on any value between $80 and $100.
D) The number of units produced in a given day, where 20% of the time 99 units are produced and 80% of the time 100 units are produced.