You have to sign in at reception         . Nobody is allowed to do it instead of you.

       A．in detail               B．in vain                 C．in person             D．in charge

You have to sign in at reception ________．Nobody is allowed to do it instead of you．

1. A.
   in detail
2. B.
   in vain
3. C.
   in person
4. D.
   in charge