单项选择题
A.A=fix(100+200*rand(5,6))B.A=fix(200+100*rand(5,6))C.A=fix(100+300*rand(5,6))D.A=fix(100+101*rand(5,6))
A.eye(size(A))B.ones(size(A))C.size(eye(A))D.size(ones(A))
A.A=eye(3)B.A=eye(3,1)C.A=eye(1,3)D.A=ones(3)