Phillip is bullish that FitBit stock, a successful diet app, is going to rise above its current price of $10 per share. Therefore, Phillip purchases 700 shares of FitBit on his trading account with Megan Sterling and buys another 300 shares on margin (at zero interest cost). One year later, FitBit's stock rose 20% to $12 per share. Please indicate the only incorrect statement about buying on margin: O a. Phillip has posted more collateral with Megan Sterling than the Fed's Reg T requires O b. If FitBit's stocks falls significantly, Phillip is subject to a 30% maintenance margin Phillip's return will amount to 71.43% C. d. Phillip's return will amount to 28.57%