Let Mn×n be the set of all n-square symmetric matrices and the characteristics polynomial of each A ∈ Mn×n is of the form:
tn + tn – 2 + an –3tn−3 + ⋯ + a1t + a0. Then the dimension of Mn×n over R is
(a) (n−1) n2 (b) (n−2) n2
(c) (n−1) (n+2)2 (d) (n−1)2 2