To compare the volumes of the two refrigerators, we can summarize the information given:
- The volume of the Hawks refrigerator is \( 30 \times 68 \times 28.5 \) cubic inches.
- The volume of the Lopezes refrigerator is \( (30 \times 68 \times 28.5) + 16 \) cubic inches.
From this information, we can see that the volume of the Lopezes refrigerator is equal to the volume of the Hawks refrigerator plus an additional 16 cubic inches.
Therefore, we can conclude that:
D: The volume of the Hawks refrigerator is 16 cubic inches less than the volume of the Lopezes refrigerator.
So, the correct statement is D.