Elizabeth swims so _____, as if it's the easiest thing in the wo

Elizabeth swims so _____, as if it's the easiest thing in the world.
A、effortlessly
B、freely
C、excitedly
D、carelessly
【正确答案】：A
【题目解析】：effortlessly轻松地，毫不费力地；freely自由地；excitedly激动地；carelessly粗心地。句意：伊丽莎白毫不费力地游泳，好像这是世界上最容易的事情。