The answer is: D. Increasing the capacity of the bottleneck increases capacity for the whole system
Companies who use bottleneck management would stock large number of their products in their disposal before eventually release them to the consumers on a large scale.
Increasing the capacity of the bottle neck does not necessarily increase the capacity of the whole system because there are limits on how much the employees (specifically the sales department) could sell. There is always a huger risk of overstock that could resulted in a huge loss for the company.