单项选择题
A.The code will compile without changes.
B.The code will compile if public Tree（）{Plant（）；} is added to the Tree class.
C.The code will compile if public Plant（）{Tree（）；} is added to the Plant class.
D.The code will compile if public Plant（）{this（"fern"）；} is added to the Plant class.
E.The code will compile if public Plant（）{Plant（"fern"）；} is added to the Plant class.
