Answer:
A) the optimal level of product availability decreases.
Step-by-step explanation:
The optimal level of product availability decreases when the ratio of the cost of overstocking to the cost of understocking increases or gets larger.
The optimal level of product availability is defined as the ratio of cost of overstocking to the cost of understocking.
Therefore, when the ratio of cost of overstocking to the cost of understocking gets larger, the optimal level of product availability decreases and vice-versa.