1/a+1/b+1/c =(a+b+c)/a+(a+b+c)/b+(a+b+c)/c =1+(b+c)/a+1+(a+c)/b+1+(a+b)/c =3+b/c+c/b+a/c+c/a+a/b+b/a ≥3+2+2+2 =9 B
