A, B, D, and E are all wrong. C is the right answer. C is a compound.
A, B, D and E are not unique. A pure substance is something with unique characteristics and if it can be broken down, the result is two or more pure substances. AKA only compounds and elements. This is an easy question so try to study.
The brain of the cell most important
This is what I found hopefully it helps :)
Answer:
MRI = Electromagnet
Moon = Not magnetic
Compass = Permanent magnet