We saw several natives advancing towards our party, and one of them came up to us, __________ we gave some bells and glasses.

A．to which

B．to whom

C．with whom

D．with which

质量为m的带电小球用绝缘线悬挂于O点，并处于水平向右的大小为E的匀强电场中（设电场足够大），小球静止时，丝线与铅垂线夹角为θ，如图所示，求：

（1）小球带何种电荷？

（2）小球电荷量为多少？

（3）若将丝线烧断，小球的加速度为多大？