单项选择题
A.1+sqrt(0.2)*randn(25,20)B.1+0.2*randn(500)C.0.2+randn(500)D.0.2+randn(25,20)
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))