The suggested answer is C, D.
A point-to-point OSPF adjacency has two main advantages. First, no type 2 LSAs are generated, which simplifies the OSPF database since type 2 LSAs are used for describing multi-access network segments like Ethernet. Second, there is quicker neighbor establishment because the formation process does not require the election of a Designated Router (DR) and Backup Designated Router (BDR), thus speeding up the convergence time.