1:how a front-loading washing machine works
Explanation:
A process description does not give information as much as it describes how a process happens. This condition is only satisfied by the first example here.
The process described there is the only part of the content and nothing else.
While the second option is similar, it describes an appliance in a manual and does not actually give a process.
Rest of the options are not even remotely close to describing a process and are just simple descriptions of various events or other content.