______ led a Roman army and invaded Britain in 54 B.C.A．Emperor ClaudiusB．Julius CaesarC．W

______ led a Roman army and invaded Britain in 54 B.C.

A．Emperor Claudius

B．Julius Caesar

C．William the Conqueror

D．Pope Gregory

请帮忙给出正确答案和分析，谢谢！