On an average day, Wilsons Meats receives 20 checks from customers that average $1,200 each. It takes half a day to process these payments and another day for the funds to become available. Wilsons also receives $48,000 of daily payments from customers who are billed and pay electronically. The electronic payments are available immediately. What is the firm's collection float?

a, -$49,800

b, -$1,800

c, $1,200

d, $1,800

e, $49,800