What defines customer success?

What defines customer success?
A . the business methodology of ensuing that customers are always on the latest software releases and subscription contracts so customers can focus on core business activities.
B . a measure of the Net Promoter Score resulting from a disciplined engagement of sales, services, marketing, and customer success teams working seamlessly together to deliver a positive experience.
C . the business methodology of ensuring that customers achieve their expected and unexpected outcomes while using the product or service.
D . the business methodology for increasing recurring revenues by minimizing the risk of churn while driving adoption and expansion.

Answer: C