Final answer:
The business function responsible for understanding customer purchasing behavior and price points is market research. This function's insights help achieve market equilibrium by informing both the company and its potential customers.
Step-by-step explanation:
The business function that has knowledge about who buys the company's products and services and how much they are willing to pay is likely the market research function. Market researchers analyze the market to understand the proportion of all people who will buy the product and at what price point. They gather data, monitor trends, and understand customer preferences to inform the company's strategies. Market equilibrium requires that both sellers and buyers have full information about the product's price and quality, and market research helps in providing that information.