1.publicinterfaceA{
2.publicvoiddoSomething（Stringthing）；
3.}
1.publicclassAImplimplementsA{
2.publicvoiddoSomething（Stringmsg）{}
3.}
1.publicclassB{
2.publicAdoit（）{
3.//morecodehere
4.}
5.
6.publicStringexecute（）{
7.//morecodehere
8.}
9.}
1.publicclassCextendsB{
2.publicAImpldoit（）{
3.//morecodehere
4.}
5.
6.publicObjectexecute（）{
7.//morecodehere
8.}
9.}
Whichstatementistrueabouttheclassesandinterfacesintheexhibit？（）