Find the characteristic polynomial and the eigenvalues of the matrix The characteristic polynomial is (Type an expression using a as the variable. Type an exact answer, using radicals as needed) Select the correct choice below and, if necessary, fill in the answer box within your choice O A. The real eigenvalue(s) of the matrix is/are (Type an exact answer, using radicals as needed. Use a comma to separato answers as needed. Type each answer only once) O B. The matrix has no real eigenvalues