please help with explanation / answer

STEP: 1 of 3 Sparkle is one firm of many in the market for toothpaste, which is in long-run equilibrium. Indicate which of the following graphs accurately reflects Sparkle's demand curve, marginal-revenue (MR) curve, average-total-cost (ATC) curve, and marginal-cost (MC) curve. (? (?) B Demand Price, Cost, Revenue Demand ATC Price, Cost, Revenue ATC MC MC MR MR Quantity of Sparkle Toothpaste Quantity of Sparkle Toothpaste O A O B