AA, PP and DD are n×nn×n matrices. Check the true statements below: A. AA is diagonalizable if A=PDP−1A=PDP−1 for some diagonal matrix DD and some invertible matrix PP. B. AA is diagonalizable if and only if AA has nn eigenvalues, counting multiplicities. C. If AA is diagonalizable, then AA is invertible. D. If there exists a basis for RnRn consisting entirely of eigenvectors of AA, then AA is diagonalizable.