a,b,c满足a+b+c=0,abc>0 => a、b、c两负一正
设 a<0, b<0, c>0. a+b = - c,ab < c^2
1/a+1/b+1/c
= (a+b) / (ab) + 1/c
= - c /(ab) + 1/c
= (-c^2 + ab)/(abc)
< 0
所以应该选B