Determinant of P is equal to 1
P is orthogonal
Inverse of P is equal to its transpose
All eigen values of P are real numbers
Answer is Right!
Answer is Wrong!
The correct answer is D.
The determinant of P is equal to 1, since it is a product of three terms, each of which is equal to $\pm 1$.
P is orthogonal, since its transpose is equal to its inverse.
The eigenvalues of P are $\pm i$, which are not real numbers.
Therefore, the incorrect statement is D.