which code segment should you replace line 24?

You are developing an application that includes the following code segment. (Line numbers are
included for reference only.)

You need to ensure that the DoWork(Widget widget) method runs.
With which code segment should you replace line 24?

A.
DoWork((Widget)o);

B.
DoWork(new Widget(o));

C.
DoWork(o is Widget);

D.
DoWork((ItemBase)o);