The property of inequality that justifies the steps shown in the solution process is the Multiplication Property of Inequality.
In this case, the equation \( \frac{3}{4} \left( \frac{4}{3} d \right) \geq -20 \left( \frac{3}{4} \right) \) involves multiplying both sides of the inequality by \( \frac{3}{4} \). Since \( \frac{3}{4} \) is a positive number, the direction of the inequality does not change. Therefore, the correct response is:
Multiplication Property of Inequality.