Why does a monopolistically competitive firm earn zero economic profits (normal profits) in the long run

During the month of march 2017, weimar world, a tax-preparation service, had the following transactions. * billed $496,000 in revenues on credit * received $164,000 from customers' accounts receivable * incurred expenses of $194,000 but only paid $87,700 cash for these expenses * prepaid $32,220 for computer services to be used next month what was the company's accrual basis net income for the month? select one: a. $302,000 b. $264,080 c. $ 41,860 d. $408,300 e. none of the above