等差数列{an}中,a100,且a10的绝对值>a11的绝对值,Sn 为数列{an}的前n项和,则（）

等差数列{an}中,a100,且a10的绝对值>a11的绝对值,Sn 为数列{an}的前n项和,则（）A S1,S2...S10都小于0,S11,S12...都大于0 B S1,S2...S19都小于0,S20,S21...都大于0 C S1,S2...S5都小于0,S6,S7...都大于0 D S1,S2...S20都小于0,S21,S22...都大于0