An investor purchased shares with a market price of $70 when the initial margin requirement was 60%. If the price increases to $92, the investor's return, ignoring dividends and interest, is closest to:

a. 31%.

b. 44%.

c. 52%.

d. 120%.

Stock purchases with a 50% initial margin and a 30% maintenance margin will be called at a:

a. 15% decrease in the price of the stock.

b. 25% decrease in the price of the stock.

c. 28.6% decrease in the price of the stock.

d. 20% decrease in the price of the stock.