Your company is planning on hosting a set of virtual machines in Azure. (the application must reside on virtual machines) They want to save on the running compute costs for the virtual machines. Can they consider using Azure Functions for this requirement?

Answer options:

A.Yes
B.No

Answer : B 
Azure Functions is a serverless compute service. Here we need to use Azure virtual machines. So Azure Functions can’t be used as the option 
You can use either reserved instances or Spot VM’s 
For more information on Azure Spot VM’s and reserved instances, please visit the below URL 

https://docs.microsoft.com/en-us/azure/virtual-machines/spot-vms
https://azure.microsoft.com/en-us/pricing/reserved-vm-instances/