Answer:
a customer is required to buy one product only if the customer also buys a second product.
Step-by-step explanation:
Tying sales means the circumstance in which a customer is needed to purchase other item so that he or she is able to acquire the commodity
So here it refers that the situation where the customer is needed to purchase one product only in the case when the customer also purchased the second product
Therefore as per the given situation, the first option is correct