a. B, C ∈ R +, and (1 + a) (1 + b) (1 + C) = 8

a. B, C ∈ R +, and (1 + a) (1 + b) (1 + C) = 8

8=(1+a)(1+b)(1+c)≥(2√a)(2√b)(2√c)
===> √(abc)≤1
===> abc≤1.