Under the rule of William the Conqueror, ______were at the botto

Under the rule of William the Conqueror, ______were at the bottom of the English feudal scale.
A、serfs
B、barons
C、knights
D、freemen
【正确答案】：A
【题目解析】：在征服者威廉统治下，处于封建制度最底层的是农奴。