Answer:
Demand deals with Sellers and Consumers.
Step-by-step explanation:
Demand is an economics term that relates the requested interest of a consumer for a product to the need of production for the product by the seller. Typically, demand goes hand-in-hand with supply. Demand is the consumer's desire for the product, while supply is the amount of the product available.
In the case of this question, Sellers and Consumers fit the best out of the available options.
[a] Buyers and Consumers are the same thing
[c] Public and Private Sectors doesn't relate to demand
[d] Buyers and investors could be considered the same thing
Cheers.