Choice A is the correct answer. Check slopes.

1. Line 1: $y = x$ (Slope 1).
2. Line 2: $y = -x$ (Slope -1).
3. Product: $1 \times (-1) = -1$.
4. Result: Yes.

💡 Strategic Tip: These are the diagonals.

Choice B is incorrect.Choice C is incorrect.Choice D is incorrect.