Final answer:
The melon's weight is best described as being between 5 lb. 14.5 oz. and 6 lb. 1.5 oz., considering the potential discrepancy of the three 2-pound weights being off by up to half an ounce each.
Step-by-step explanation:
We need to determine the possible range of the melon's weight balanced by three 2-pound weights, with each weight possibly being off by no more than one-half of an ounce. Given that each weight can be up to half an ounce off, this means the total potential discrepancy could be as much as 1.5 ounces (half an ounce for each of the three weights).
If the weights were all half an ounce under the actual weight, the melon would weigh up to 1.5 ounces more than 6 pounds (the total of three 2-pound weights). Conversely, if the weights were all half an ounce over the actual weight, the melon would weigh up to 1.5 ounces less than 6 pounds.
Therefore, the weight of the melon could be described as being between 5 lb. 14.5 oz. and 6 lb. 1.5 oz. Hence, option D is the correct description of the melon's weight.