Gross weight is relative to net weight, that is, net weight is the weight of goods or commodities excluding packaging, while gross weight refers to the weight of goods or commodities including packaging, that is, gross weight = net weight+packaging weight.

For example:

A bucket of water, in which the water weight is 10 kg and the bucket weight is 0.5 kg.

When the answer is that the weight of a bucket of water is 10.5kg, it refers to the gross weight.

When the weight of a bucket of water is 9.5 kilograms, it means the net weight.

Net weight of water = gross weight-barrel weight

So the answer is B.