An organization with a large IT department has decided to migrate to AWS. With different job functions in the IT department, it is not desirable to give all users access to all AWS resources. Currently the organization handles access via LDAP group membership.
What is the BEST method to allow access using current LDAP credentials?

A. Create an AWS Directly Service Simple AD. Replicate the on-premises LDAP directory to Simple AD.
B. Create a Lambda function to read LDAP groups and automate the creation of IAM users.
C. Use AWS CloudFormation to create IAM roles. Deploy Direct Connect to allow access to the on-premises LDAP server.
D. Federate the LDAP directory with IAM using SAML. Create different IAM roles to correspond to different LDAP groups to limit permissions.