When using virtual inventory instead of physical inventory, enterprises face three challenges:

First, the impact of basis change on futures level.

Second, the impact of futures monthly spread.

Third, there are some non-price uncertainties in spot procurement, including insufficient supply in some areas, unqualified quality or poor traffic in future procurement.

The establishment of virtual inventory is to buy futures instead of spot, and enterprises need to consider the influence of the change of basis (spot price-futures price) rather than the change of spot price, so item A is not selected in this question.