Answer:
c. B2C
Step-by-step explanation:
Online banking is an example of B2C (Business to Consumer). Here the banking service provider is the designated business. Whereas the customers of the bank who access their accounts online constitute the C on B2C.
The other options:
B2B - Business to Business is relevant for transaction involving two business entities.
C2C - Customer to Customer is a peer transaction among customers
SaaS - Software As A Service where a software vendor make their product available on cloud.