According to the WS), what was the reason (the actual reason not the potentially rumored reason) for the broker Robinhood halting new purchases of GameStop stock and other stocks in late January 2021? O A. They were trying to help hedge funds who had made bets the stock would fall B. If Robinhood wanted to keep collecting payment for order flow, they were required to stop allowing new purchases until the stock volatility was lower C. The dramatic increase in stock price volatility of GameStop and other stocks had led to a massive increase in the margin requirements for Robinhood by the stock clearinghouse and halting some trading reduced margin requirements D. A & C only E. All of the above