People Who Accept the Efficient Markets Hypothesis Should

People who accept the efficient markets hypothesis should:

A) buy a large number of stocks from different companies and hold them for a long period.
B) buy a small number of stocks from several companies, selling the stocks whose price has fallen and keeping the rest.
C) buy stocks only at a low price and sell them when their prices have increased by more than the market average.
D) constantly buy and sell stocks to avoid the risk of large price swings.