Answer:
The correct option is D
Explanation:
This question is incomplete because of the absence of the setup which as been attached below. The setup shows/determines/tests the friction of wood (which is a block material), since Jerry wants to test the friction between different types of materials, he will have to replace the wooden block with another type of block material of choice so as to determine the friction of that also.
In order to have a comprehensive experiment, Jerry can use 4-5 different types of block material in the course of the experiment.
