Answer: c. upselling
A sales person who convinces a customer to buy a more expensive product than the customer originally intended is using upselling sales technique.
Explanation:
Upselling refers to a sale technique used by a sales person or seller in convincing a customer in order to buy a good or product that is more costly than the good he or she wanted to buy initially. The sales person does this in order to make good profit. Hence, upselling brings the sales person closer to the customer.