John ,you work much harder this term than before . Yeah ,_A_

John ,you work much harder this term than before . Yeah ,_A___ and ___in our class because we a...
John ,you work much harder this term than before .
Yeah ,_A___ and ___in our class because we are Grade 3 .
A.so I do ,so do others B.so you do , so do others
C.so do you ,so others do D.so do I ,so others do 可以讲一下为什么选A吗