Explanation
Option C is correct because it allows the administrator to configure the mail server settings in the vCenter settings in the vSphere Client, which are required for sending email notifications for alarms. Option A is incorrect because it configures the mail server settings on an ESXi host system, which are not used for sending email notifications for alarms. Option B is incorrect because it configures the alarm rule definitions, which are already enabled in the exhibit. Option D is incorrect because it configures the vCenter Management Interface, which is not used for sending email notifications for alarms. References:
https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.monitoring.doc/GUID-A2A4371A-B88