Question

Question was provided via image upload.

Explanation:

Step1: Analyze Step 4 operation

Step 4 removes parentheses by distributing the negative sign: $(x^2 + 2xy + y^2) - (x^2 - 2xy + y^2) = x^2 + 2xy + y^2 - x^2 + 2xy - y^2$. This uses $a - (b - c + d) = a - b + c - d$, which is the distributive property of multiplication over subtraction.

Step2: Match with options

Option A is the distributive property; others don’t apply here.

Answer:

A. Distributive property