You need to identify a transition path for the company

A company has an existing on-premises Active Directory environment that is synchronized using DirSync. They
plan to transition the DirSync deployment to Azure Active Directory (Azure AD) Connect.
You need to identify a transition path for the company.
What should you do?

A.
Install a new on-premises domain controller.

B.
Create a new Azure AD instance.

C.
Upgrade the on-premises Active Directory Domain Service (AD DS) forest functional level to Windows
Server 2016.

D.
Deploy Azure AD Connect in parallel.

Explanation:
https://docs.microsoft.com/gl-es/azure/active-directory/connect/active-directory-aadconnectdirsync-deprecated#how-to-transition-to-azure-ad-connect