An investor buys $10,000 worth of a stock priced at $50 per share using 50% initial margin. The broker charges 10% on the margin loan and requires a 30% maintenance margin. In one year the investor gets a margin call. At the time of the margin call the stock's price must have been ____.

A. $40.00 B. $39.29 C. $33.15 D. $30.45