Consider the following method, which is intended to return the product of 3 and the nonnegative difference between two int parameters.

public int threeTimesDiff(int num1, int num2) { return 3 * (num1 - num2); }

Which precondition is required so that the method works as intended for all values of the parameters that satisfy the precondition?

• num1 > 0, num2 > 0

• num1 >= 0, num2 >= 0

• num1 >= num2

• num2 >= num1