Please answer the following question given the answers below, showing ALL WORK.

Inside Traders opens a brokerage account and purchases 500 shares of Energy Infusion at $70 per share. They borrow $20,000 to pay for the stock. The interest rate on the loan is 7%. If the maintenance margin requirement is 25%, how low can the stock price go in one year before a margin call would be made?

a. 34

b. 68

c. 47

d. 57

e. 25