Let G be a group with identity e. Let H be an abelian non-trivial proper subgroup of G with the property that HogHg = {e for all geH. If K={g e G :gh = hg for all he H} , then (a) K is a proper subgroup of H (b) H is a proper subgroup of K (c) K = H (d) There exists no abelian subgroup LcG such that K is a proper subgroup of L [2020 2 Marks]