During September, the capital expenditure budget indicates a $420,000 purchase of equipment. The ending September cash balance from operations is budgeted to be $60,000. The company wants to maintain a minimum cash balance of $30,000. What is the minimum cash loan that must be planned to be borrowed from the bank during September?

a, $330,000
b, $360,000
c, $450,000
d, $390,000