Query about Question 4 from "Timed Quant Practice - Medium Section 2 Sample Test #1" [9049]

https://www.gregmat.com/quizzes/quiz/timed-quant-practice-medium-section-2-sample-test-1-mqk7 (Question 4)


Shouldnt the answer to this be D, can’t determine, because it doesnt specify that the integers are positive? So it could be 456 , but it could also be negative 456, in which case multiplying them would still be 120 but adding them would be -15?

How?