You are planning an AD Connect strategy to utilize leaked credentials detection in Azure AD Identity Protection. What must you enable?

Answer options:

A.Password writeback
B.Device writeback
C.Password hash synchronization
D.Pass-through authentication

Correct Answer: C 
Password Hash Sync enables the Azure AD Identity Protection leaked credentials feature, who monitors public web sites and the dark web for username/passwords from malicious sites.
Option A is incorrect. This feature within Azure AD Connect allows password changes in the cloud to be written back to an on-premise directory.
Option B is incorrect. This feature within Azure AD Connect synchronizes devices registered in Azure AD back to on-premise.
Option D is incorrect. Pass-through authentication does not support detection of users with leaked credentials.
Reference: 
To know more about Password hash synchronization, please refer to the link below: 

https://docs.microsoft.com/bs-latn-ba/azure/active-directory/hybrid/whatis-phs