Which expression is equivalent to the expression open parentheses x to the power of 2 minus y to the power of 2 close parentheses to the power of 2 ? open parentheses x to the power of 2 plus y to the power of 2 close parentheses open parentheses x plus y close parentheses open parentheses x minus y close parentheses open parentheses x plus y close parentheses to the power of 2 open parentheses x minus y close parentheses to the power of 2 2 open parentheses x plus y close parentheses open parentheses x minus y close parentheses x to the power of 4 minus y to the power of 4