Which is a valid abstract class?

Which is a valid abstract class?

A.
public abstract class Car { protected void accelerate(); }

B.
public interface Car { protected abstract void accelerate(); }

C.
public abstract class Car { protected final void accelerate(); }

D.
public abstract class Car { protected abstract void accelerate(); }

E.
public abstract class Car { protected abstract void accelerate() { //more car can do
}}