If a*b=b*a, then the operation is commutative. If (a*b)*c=a*(b*c), then the operation is associative. By option (d) ‌a*b=a+b+ab ‌b*a=b+a+ba=a+b+ab Here, a*b=b*a, so the operation is commutative. (a*b)*c‌=(a+b+ab)*c ‌=(a+b+ab)+c+(a+b+ab)c ‌=a+b+ab+c+ac+bc+abc ‌=a+b+c+ab+ac+bc+abc a*(b*c)‌=a*(b+c+bc) ‌=a+b+c+bc+a(b+c+bc) ‌=a+b+c+bc+ab+ac+abc Here, (a*b)*c=a*(b*c). So, the operation is associative.