Answer:
c. $25.2 million
Step-by-step explanation:
Billy's Burgers' Accounts receivable 2011 = Accounts receivable 2010 *(1+Growth rate)
Billy's Burgers' Accounts receivable 2011 = $21,000,000 * (1+0.20)
Billy's Burgers' Accounts receivable 2011 = $21,000,000 * (1.20)
Billy's Burgers' Accounts receivable 2011 = $25,200,000.