请选择CBA.X0q'B4\7p,]8?,IPlease be quiet! Dad ______ working in the room.,C+x2H1{0z-e:i1P
A. am,C+x2H1{0z-e:i1P
B. is,C+x2H1{0z-e:i1P
C. are,C+x2H1{0z-e:i1P