某工厂有100台机器，拟分4期使用，在每一周期内有两种生产任务。据经验把x₁台机器投入第一种生产任务，则在一个生产周期中将有(1/3)x₁台机器作废；余下的机器全部投入第二种生产任务，则有1/10机器作废。如果第一种生产任务每台机器可受益10单位，与第二种生产任务每台机器可受益7单位。问应怎样分配机器才能使总收益最大？

A．Because people like diet, liposuction, or breast implant to make themselves more attractive
B．People want to conform to the beauty standard in the society
C．Because people attach great importance to their health
D．Because people are fascinated by their own body