Which one is a good example of Straddling, similar to the example explained in the textbook?

a$.$

Increasing the number of product varieties, keeping the company competing at the same level as before.

b$.$

A new process that allows customers to leave their parcels at a centralized retail store, increasing "the business" for the company.

c$.$

A company that for every sale, give a basketball ticket to the customer, but this added benefit has not increased sales.

d$.$

Customers that complaints, get a $10\%$ discount in the next purchase.