As Shown in the Figure Below, R1 and R2 Are

As shown in the figure below, R1 and R2 are connected through a PPP link, and the IP addresses on the directly connected interfaces are not on the same network segment. R1 and R2 can communicate with each other through the directly connected interfaces. However, communication on the Ethernet link fails if the IP addresses on the directly connected interfaces are on the same network segment. What are the causes of this?

A) The Ethernet header does not need to be encapsulated into data packets between R1 and R2 that are directly connected through a POS interface, and ARP does not need be used to obtain MAC addresses.
B) R1 and R2 that are directly connected through a POS interface learn the MAC address of each other using LCP, and ARP does not need to be used to obtain MAC addresses.
C) R1 and R2 that are directly connected through a POS interface learn the 24-bit subnet route of each other through IPCP.
D) R1 and R2 that are directly connected through a POS interface learn the 32-bit host route of each other through IPCP.