A mixture can be separated by all of the following EXCEPT Filtration
Distillation
Sieving
A magnet
Evaporation
All are methods to separate mixtures

All are methods to separate mixtures

Explanation:

A mixture consists of 2 or more substances that are mixed physically but not chemically. Hence, mixtures can be separated by any physical separation means which include but not limited to filtration, distillation, sieving, magnetization, and evaporation.

Filtration is usually used to separate suspended particles in a liquid using a membrane of a filter paper. Distillation is used to separate miscible liquids with varying boiling points by evaporating and condensing them back at their respective boiling points. Sieving is used to separate mixtures with varying particle sizes of individual components.

Magnetization is usually used to separate mixtures with, at least, one component with magnetic property. Evaporation is used to separate dissolved solids from liquids.

Hence, all the methods listed are used to separate mixtures.

your answer should be c) enjoy!