Final answer:
The floc point is the temperature at which wax first is noticed separating from the oil, often observed during the fractional distillation of crude oil, where components condense at different levels based on their boiling points.
Step-by-step explanation:
The floc point refers to (B) the temperature at which wax first is noticed separating from the oil. In the context of fractional distillation of crude oil, crude oil is heated to high temperatures and vaporized when entering the base of the distillation column. As the vapors cool while rising through the column, different components with varying boiling points condense at different levels and are collected.
During the distillation process, some hydrocarbons may begin to solidify into wax, which can be observed at the floc point. This is distinct from other terms mentioned in the options, such as the flash point, which is the temperature at which oil vapor will flash when exposed to a flame, or carbonization, which is when oil turns into carbon upon contact with hot surfaces.