As of January 1 of the current year, Gunner Company had accounts receivable of $50,000. The sales for January, February, and March were $120,000, $140,000, and $150,000, respectively. Of each month's sales, 20% are for cash. Of the remaining 80% (the credit sales), 60% are collected in the month of sale, with the remaining 40% collected in the following month. The accounts receivable balance as of March 31 is

a.$72,000

b.$60,000

c.$48,000

d.$58,720