The correct option is A sediment
The insoluble solids that settles down at the bottom when a solid-liquid mixture is left undisturbed is called sediment. The stones and mud in a pond are examples of sediment. This is because they settle down as the pond is a stationary water body.
However, filtrate is the liquid obtained during filtration. Decantate is the top most layer that is poured out during decantation. Also, solvent is a term used to define the component that is present in a larger amount in a solution.