the properties of an orthogonal matrix :
1. It preserves lengths.
2. It preserves angles
By above properties , Options B and C = False
Now Option A :
If Mx = 0, this means the matrix maps a non-zero vector to the zero vector.
A rotation/reflection cannot do this. If a non-zero vector is rotated, its length
remains the same, so it can't become the zero vector.
An orthogonal matrix is always invertible, and its determinant is non-zero.
The only vector it maps to zero is the zero vector itself.
Conclusion: The statement is False.