a) Let p be a prime, and let F be the finite field of order p. Compute the order of the finite group GLK (Fp) of k x k invertible matrices with entries in Fp. b) Identify F with the space of column vectors of length k whose entries belong to Fp. Multiplication of matrices gives an action of GL (Fp) on F. Let U be the set of non-zero elements of F. Prove that GLK (Fp) acts transitively on U. c) Let u be a fixed non-zero element of F. Let H be the subgroup of GLk (Fp) consisting of all A such that Au = u. Compute the order of H.