Stress equals force per unit area, identical for both wires

Steps:

• Stress = load / cross-sectional area; loads and areas are equal, so stress is the same.
• Strain = extension / original length; lengths are equal, but extensions differ due to material properties.
• Young's modulus Y = stress / strain; equal stress but different strains mean different Y values.
• Only stress is equal; strain and Y vary by material.

Why A is correct:

• Stress is defined as force divided by area; identical loads and areas ensure equal stress.

Why the others are wrong:

• B: Strain differs as copper and steel have different elastic properties, causing unequal extensions.
• C: Strain and Y differ due to material-specific responses to the same stress.
• D: Strain and Y differ, while only stress is equal.

Final answer: A