The correct answer is "A".
One of the principles of Economic theory is scarcity. Scarcity is the limited availability of certain good. The value of this goodwill grow or decrease according to its demand.
In the economic environment, there are many participants. many of them have interests that enter in conflict with one another. This means that, following the previously mentioned concept of scarcity, at the end of a period there will be winning stakeholders and losing stakeholders. "One's loss is another's gain".