Cores used in PMC are usually made up of? A. Metal B. Collapsable

cores-used-in-pmc-are-usually-made-up-of-a-metal-b-collapsable

Cores used in PMC are usually made up of?

A. Metal

B. Collapsable material

C. Sand

D. All of the mentioned

I have been asked this question in unit test.

My query is from Special Casting Techniques in section Special Casting Techniques of Casting-Forming-Welding I

Right choice is D. All of the mentioned

The explanation: In PMC the cores can be made out of any of these materials.