you go to a friend's house . it is the first time you go to the house . A man , whom you don't know , opens the door . you ask ....? A. may i go in. B. is this

you go to a friend's house . it is the first time you go to the house . A man , whom you don't know , opens the door . you ask "....?
A. may i go in.
B. is this sandrina ' s home
C. is sandrina at home.
D. Do you know sandrina