1. The problem involves interpreting a stress-strain curve and selecting the correct statement about material behavior. 2. Key concepts: - The modulus of elasticity (Young's modulus) is the slope of the stress-strain curve in the elastic region, typically at very low strains (0% to 1%). - The necking region occurs after strain hardening, where the material starts to thin and the curve drops. - Yielding region is where the material deforms plastically at nearly constant stress. - Fracture strain is the strain value at which the material breaks. 3. Analyze each option: - a. Necking region is approximately equal to strain hardening region: Usually, strain hardening precedes necking and they are not equal in length. - b. Modulus of elasticity can be determined within 0% to 1% strain: This is true because the initial linear portion of the curve represents elastic behavior. - c. Yielding region is smaller because specimen is perfectly plastic: Perfectly plastic materials have a distinct yield plateau, so this can be true depending on the curve shape. - d. Fracture strain is 0.13 mm/mm since strain at fracture is 13%: Strain in % divided by 100 gives strain in mm/mm, so 13% = 0.13 mm/mm, which is correct. 4. The best correct statement is d, as it correctly converts percentage strain to engineering strain units. Final answer: d. The specimen's fracture strain is 0.13 mm/mm since the percentage strain at which it occurs is 13%.