Let AAA and BBB be n×nn \times nn×n matrices. If AB=0AB = 0AB=0, which of the following is necessarily true?
det(A)=0\det(A) = 0det(A)=0 or det(B)=0\det(B) = 0det(B)=0
A=0A = 0A=0 or B=0B = 0B=0
BA=0BA = 0BA=0
AAA and BBB are singular