Which of the following service falls under the category of serverless computing?

Answer options:

A.Azure virtual machines
B.Azure SQL database – Elastic pool
C.Azure Functions
D.Availability sets

Answer : C 
Azure Functions is an example of serverless computing. Here the underlying compute infrastructure is managed by the service itself.
Option A is incorrect because the virtual machine service is an Infrastructure as a service.
Option B is incorrect because the Azure SQL database – Elastic pool is a platform as a service.
Option D is incorrect because this is used to manage the availability of virtual machines
For more information on serverless computing, please visit the below URL 

https://azure.microsoft.com/en-us/overview/serverless-computing/