My mother is busy----her work.A,at B,with C.in D.from ----fi

My mother is busy____her work.A,at B,with C.in D.from ____finish at 2:00.Which is wrong?A.Class 1.My mother is busy____her work.A,at B,with C.in D.from 2.____finish at 2:00.Which is wrong?A.Class all B.All the classes C.All of my class D.All classes