Kempton invests $1,000 in a company when the price of its stocks is high. He doesn't sell it until its price goes down. According to the basic rule of investing, what did Kempton do wrong? A
He should have waited for the stock's price to go up even higher before buying it.

B
He should have invested more money in this company.

C
He should have sold the stock the day after he bought it, whether its price went up or down.

D
He should have bought stock in a company when the price was low and sold it when the price went up.