— ______________ jacket is this?

— Maybe it's Tom's. [ ]

A. Who

B. What

C. Whose

D. Where

下列有关说法正确的是（ ）                                                   

A．能在水溶液或熔融状态下导电的物质是电解质

B．电离出氢离子的化合物是酸

C．纳米材料也是一种胶体

D．丁达尔效应，是胶体粒子对光散射形成的