Which of the following memories contains a thin film of magnetic material sandwitched between two permanent bias magnets?

Magnetic-core memory (core memory) was the predominant form of RAM memory in b/n 1955 and 1975. Core uses tiny magnetic rings through which wires are threaded to write and read information. Core memory often refers to just the central RAM of a computer that stores programs that are currently running and that data that they are working on.