The old man walked in the street, _____. [ ]

A. followed by his son

B. followed his son

C. and following his son

D. and followed by his son

配比型电子皮带秤控制系统以通过主秤的物料瞬时流量为基准，与掺配称量装置相对应的设定掺配（）运算后，作为该掺配装置的设定流量。

A.质量

B.重量

C.比例

D.流量