What command is used to save a workspace variable in MATLAB?

The command used to save a workspace variable in MATLAB is "save". This command allows users to store variables from the workspace into a MATLAB data file with the specified filename. When you execute the save command, it can save all the current workspace variables or specific ones if you provide their names. This capability is crucial for preserving data between different sessions, conducting analyses, or sharing your work with others.

Using save ensures that all workspace variables are securely saved into a format that MATLAB can easily load later. The other options listed, like store, backup, and keep, do not represent valid MATLAB commands for this purpose and would not function as required for saving workspace variables.