Which of the scripts that follow creates a matrix N which is normal. Remember a normal matrix is one that commutes with its transpose, in other words N*N' is the same as N'*N. User matlab to check.

To check compute the norm of the difference between N'*N and N*N'. If it is a tiny number it is normal.

a.

N = rand(3,3)-rand(3,3);

b.

N = rand(3); N = N+N^-1

c.

N = rand(3); N = N-N'

d.

N = rand(3,3)+rand(3,3);

e.

N = rand(3); N = N-N^-1

Clear my choice