Pls give me the answers and show how to get it

[MUST SHOW WORK] In Kingston, ON, three businesses offer to paint your house. At a price of $150, business A is willing to supply 10 house paintings each month. At the same price of $150, business B is willing to supply 20 house paintings each month and business C is willing to supply 30 house paintings each month. The market supply of house paintings in Kingston, ON, at a price of $150 is Select one: O A. 90 house paintings per month. O B. 30 house paintings per month. O C. 60 house paintings per month. O D. 20 house paintings per month. O E. Impossible to determine without more information