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
All of the following are true about property of polymethyl methacrylate except: 
Select and explain. 
A. KHN 18-20, B. chemical stable if heated till 260 degree F, C. Modulous of elasticity is 2.4 Gpa., D. Tensile strength 29Mpa.
D: Tensile strength 29Mpa.
Answer: D: Tensile strength 29Mpa. 
Explanation: It is a hard resin with a Knoop hardness number of la to 20 KHN.
It has a tensile strength approximately 60 MPa a density of 1.19 g/ cm3, and a modulus of elasticity of approximately 2.4 GPa.
It is chemically stable to heat below 125°C (About 260°F), softens at 125°C, and can be molded as a thermoplastic material.