What is the factored form of the following expression?

x^2 - 10xy + 21y^2

(1 point)

(x - 3y)(x - 7y)

(x + 3y)(x - 7y)

(x + 3y)(x + 7y)

(x - 3y)(x + 7y)

The factored form of the expression x^2 - 10xy + 21y^2 is (x - 3y)(x - 7y).