The correct command to authenticate the OSPF neighbor between PE-A and PE-B using MD5 is found in Option A. In this option, the command ip ospf message-digest-key 1 md5 44578611 is used to configure OSPF MD5 authentication on an interface with the key ID as 1 and key string as 44578611. The second command ip ospf authentication key-chain 44578611 is used to enable OSPF authentication on an interface and associate it with a specific key chain. Reference := Cisco - Implementing and Operating Cisco Service Provider Network Core Technologies

Model-driven telemetry (MDT) utilizes YANG models to enable the subscription to specific data items that are streamed from network devices. This allows applications to receive near real-time updates without the need for traditional polling methods. MDT with YANG provides a more efficient and scalable way to monitor network devices by pushing updates to subscribers, which can specify the exact data they require2.

To achieve this, we need to apply an access control list (ACL) on PE-R9 that permits SSH traffic from the management network 192.168.0.0/16 while denying other traffic. The correct ACL configuration is as follows:
access-list 100 permit tcp 192.168.0.0 0.0.255.255 any eq 22
access-list 100 deny ip any any
The first line permits TCP traffic from the management network to any destination with destination port 22 (SSH).
The second line denies all other IP traffic.
Reference:
Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) v1.0 course materials.
Cisco Learning Network: SPCOR Training Videos
Cisco Learning Network: Service Provider Training