When is the page file for a Windows guest OS or the swap partition for a Linux guest OS created?

When is the page file for a Windows guest OS or the swap partition for a Linux guest OS created?

A.
When a Virtual Machine is first powered on

B.
When the Virtual Machine is created

C.
When a reservation is set for the Virtual Machine

D.
When the Guest OS is installed on the Virtual Machine

Explanation:
When is the page file for a Windows guest OS or the swap partition for a Linux guest OS created?