The correct answer is B. In AWS Organizations, for permissions to be effective for a specific account, an explicit Allow statement must exist at every level from the root through each OU in the direct path to the account, including the account itself. Removing the FullAWSAccess policy and replacing it with a policy that only allows actions on Amazon EC2 resources means users in the Development OU will only have permissions for EC2 actions. All other actions will be explicitly denied. This ensures that actions not explicitly allowed are denied by default.