An organization is working on updating test cases for a particular module of their software.

Sam updated a set of test cases yesterday and saved the new version on his PC.

Unfortunately, the hard disk of his PC crashed, and his work was lost.

The IT department of the organization restored the contents of his hard disk with the last available back-up - from the previous morning. However, the changes made by him yesterday were lost forever.

Which of the following tools, had it been used, would have prevented the loss of Sam's updates?