What these Azure Security Center Recommendations are actually

1. Designate up to 3 owners on your subscription (Preview) - This recommendation asks to reduce the number of owners on the subscription Please ask customer to suggest which 3 to keep..
2. Install a vulnerability assessment solution on your virtual machines - This recommendation requires a third party solution which should be purchased first.. 
3. Disable unrestricted network access to storage account (Preview) - This recommendation tells you to Disable the option of allowing unrestricted network access in your storage account firewall settings. Instead, configure network rules so only applications from allowed networks can access the storage account. To allow connections from specific internet or on-premise clients, access can be granted to traffic from specific Azure virtual networks or to public internet IP address ranges. Ask client if want to limit the access to the storage accounts and tell us how they would prefer to restrict the access from given above statement..
4. Endpoint Protection not installed on Azure VMs - This recommendation is asking to install MS Anti Malware.. 
5. Remove external accounts with owner permissions from your subscription (Preview) - This recommendation is asking to remove the access to external user accounts.