This question has a three part answer, with each part broken out below:
A. To record the purchase there is a debit to Purchases and a credit to Accounts Payable, each for $75,000.
B. To record the return there is a debit to Accounts Payable and a credit to Purchases Returns and Allowances, each for $9,000.
C. The amount of the payment is $75,000 - 9,000, which is $64,000. They are paying during the discount period, so will only be paying 98% of this amount, which is $62,720.
The entry is a debit to Accounts Payable for $64,000, a debit to Purchases Discounts for $1,280, and a credit to Cash for $62,720.