Question $6$

Programming language $C++$ allows two forms of comments:

A$.//$ for a single line, ${?}^{****}$ for block lines

B$.//$ for a single line, $/*..*/$ for block lines

C$.//$ for a single line, $//...//$ for block lines

D$.//$ for a single line, $\frac{?}{{?}^{**}}$ for block lines