正确答案是B,但是句子的主语肯定少了复数形式.整个句子是:
This flowers can be planted easily in home gardens but_they require plenty of water and not too much sun.
这是一个并列句,其他的选项都错,因为ACD三个是非谓语动词,但句中有个连词BUT,所以不能选.
也可以改为:
This flower can be planted easily in home gardens but requires plenty of water and not too much sun.