Identify the accurate statement from the following options:

Explanation

Option B is correct because a hopper is defined as a small bin with a sloped bottom to facilitate material flow. The other statements are inaccurate: the angle of repose is generally less than or equal to the angle of slide; silos are typically tall and narrow rather than short and wide; and pine oil is indeed used as a modifying agent in froth flotation but the statement in option D is incomplete or less precise.