选c 设握数a+b=t>0(a-1)/b+(b-1)/a+1=0(a-1)/b+1+(b-1)/a+1 =1(a+b-1)/段蠢首b + (a+b-1)/a =1 (a+b-1)(a+b)=ab ≤档码(a+b)²/4 (t-1)t≤t²/4 t>0 解得1<t≤4/3
选 D
选A
b