Final answer:
The best option for a PC user joining a MS Teams meeting without the app installed would be to use the web app.
Step-by-step explanation:
The best option for a PC user joining a MS Teams meeting without the app installed would be to use the web app.
The web app allows users to join meetings directly through their web browser without the need to install any additional software. This is convenient for users who may not have administrative privileges to install applications on their computer or who simply prefer not to download and install software.
The other options, such as using the desktop app, mobile app, or calling in by phone, may require additional steps such as downloading and installing the app or dialing in with a phone number. The web app provides a straightforward and accessible option to join a MS Teams meeting without any additional hassle or requirements.