Using the Ubuntu $20\mathrm{.}04$ virtual machine, open a command$-$line interface $($shell$).$ To do so$,$ click on the bottom left $9-$dotted grid $($applications menu$)$ and type $$Terminal$.$ Then, click on the icon shown at the top $($likely the only application with this name$).$

Execute $$sudo apt$-$get update$$ to get the latest package information from the software repository. What directory is the file sources.list in$?$