The property that justifies the step from \(43d \geq -20\) to \(34(43)d \geq -20(34)\) is the Multiplication Property of Inequality.
This property states that if you multiply both sides of an inequality by a positive number, the direction of the inequality remains the same. In this case, multiplying both sides by \(34\) (which is positive) maintains the inequality.
So the correct response is Multiplication Property of Inequality.