This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Compressive stress is computed by dividing the
external force by the: 
Select and explain. 
A. Area of the test specimen upon which the weight rests, B. Elasticity of the test specimen in strain, C. Length of the test specimen beneath the force, D. Strain of the test specimen per unit Length
A: Area of the test specimen upon which the weight rests
Answer: A: Area of the test specimen upon which the weight rests 
Explanation: COMPRESSIVE STRESS
When a body is placed under a load that tends to compress or shorten it, the internal resistance to such a load is called a compressive stress. A compressive stress is associated with a compressive  strain. To calculate compressive stress, the applied force is divided by the cross-sectional area perpendicular to the axis of the applied force.
Key Concept: To calculate compressive stress, the applied force is divided by the cross-sectional area perpendicular to the axis of the applied force.
Phillips dental materials 12th edition page no 51