An administrator has found a free app on the AppExchanged and would like to install...

Before installing a managed package from the AppExchange, the administrator should take into consideration several factors, such as:

Custom objects and custom fields used by the app count against the org’s limits. The administrator should check how many custom objects and fields are available in their org and how many are used by the app.

Apps may require certain Salesforce editions or features to be enabled. The administrator should check the app’s requirements and compatibility with their org’s edition and features.

Apps may require external, third-party web services to function properly. The administrator should check if the app integrates with any external services and if they need to set up any authentication or configuration for them.

The other two options are incorrect because:

Managed apps do undergo a formal security review by Salesforce before they are listed on the AppExchange.

Apps can be installed in a sandbox before they are installed in production.