Concept:Simplify the logarithm of the given expression using the product law and power law of logarithms.Explanation:Given that y=8m, take logarithms on both sides.logy=log(8m)Apply the product law log(AB)=logA+logB.logy=log8+logmSince 8=23 and m=m21, rewrite the terms accordingly.logy=log(23)+log(m21)Now apply the power law log(an)=nloga.logy=3log2+21logmThis result matches the expression given in option D.Answer:Option D: logy=3log2+21logm