You uploaded a private key certificate named Cert1.pfx to App1. Which apps can use Cert1?

When you upload a private key certificate (.pfx) directly to an Azure App Service app, that certificate is bound specifically to that single app. It is not automatically shared or accessible by other apps, even if they are in the same App Service Plan or resource group. To use the same certificate with multiple apps, you would typically upload it to Azure Key Vault and then grant each app the necessary permissions to access it from Key Vault. Therefore, only App1 can use Cert1 in this scenario. The other options are incorrect because they imply automatic sharing of the certificate, which does not happen when a certificate is uploaded directly to an individual App Service app.