Answer:
Option A is the correct choice.
Step-by-step explanation:
Let d be the number of boxes of duck calls and t be the number of boxes of turkey calls.
We have been given that a company sells boxes of duck calls for $35 and boxes of turkey calls (t) for $45, so the revenue earned from selling d boxes of duck and t boxes of turkey call will be 35d and 45t respectively.
Further, the company plan to make $300. We can represent this information as:

We are also told that they make batches of duck calls that fill 6 boxes and batches of turkey calls that fill 8 boxes. the company only has 42 boxes. We can represent this information as:


Therefore, our desired system of equation will be:

I believe this would be a contingent discount. Contingent discounts are granted to a buyer when they satisfy certain requirements. In this case, the requirement is to have a minimum purchase of $500. Thus, that would make it a contingent discount.
The other's are incorrect.
A membership discount requires you to have a membership.
A straight discount is basically present value of future cash flow without compounding. (Business Dictionary Definition)
A bulk purchase discount is a financial incentive for regular shoppers or businesses that buy things in bulk.
You just have to divide the amount spent by the number of golf balls.
$9.54 divided by 18 balls = $0.53 per golf ball