Pick out the correct statement.

A. Angle of repose is always greater than the angle of slide

B. A hopper is a small bin with a sloping bottom

C. A silo is a short height vessel of very large diameter used for the storage of high volatile matter coal

D. Pine oil is used as a 'modifying agent' (for activating or depressing the adsorption of filming agents) in froth floatation process

Answer: Option B