On ESXi, how is the parent-child relation determined between the base disk file and it's delta files, when a snapshot of a VM is taken.

On ESXi, how is the parent-child relation determined between the base disk file and it's delta files, when a snapshot of a VM is taken.

• Through VMFS metadata
• Through ESXi database
• Through .vmx file
• Through .vmdk descriptor file 

EXPLANATION

 Delta disk files: A .vmdk file to which the guest operating system can write. The delta disk represents the difference between the current state of the virtual disk and the state that existed at the time that the previous snapshot was taken. When you take a snapshot, the state of the virtual disk is preserved, which prevents the guest operating system from writing to it, and a delta or child disk is created. A delta disk has two files, including a descriptor file that is small and contains information about the virtual disk and a corresponding file that contains the raw data. The files that make up the delta disk are referred to as child disks or redo logs.