The PMI, Inc. processes an estimated 200,000 checks per year from its customers. Total revenue collected by check is $40,000,000. The average float time until the funds are credited to PMI's checking account is 6 days. For an extra cost of $ .06/check, PMI's bank will install a lock-box system that will reduce float time from 6 days to 2.5 days. If PMI earns 3.5% on its checking account, how much per check will PMI make if it uses the lock-box system?

a. $.005

b. $.006

c. $.007

d. $.008