Which PPP subprotocol negotiates authentication options?

A.
NCP

B.
ISDN

C.
SLIP

D.
LCP

E.
DLCI

Explanation:
The PPP Link Control Protocol (LCP) is documented in RFC 1661. LPC negotiates link and PPP
parameters to dynamically configure the data link layer of a PPP connection. Common LCP
options include the PPP MRU, the authentication protocol, compression of PPP header fields,
callback, and multilink options.