Kyra has set up a remote access server $($RAS$)$ in her organization. She has also configured VPN access on the NAT router. Next, she needs to set up the client systems that will be allowed to access the RAS. Kyra wants to ensure that the client and server communicate using the most secure authentication method.

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Which of the following methods should Kyra ensure is supported on both the client and the server?

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a$.$

Password Authentication Protocol $($PAP$)$

b$.$

Challenge Handshake Authentication Protocol $($CHAP$)$

c$.$

Microsoft Challenge Handshake Authentication Protocol version $2($MS$-$CHAP v$2)$

d$.$

Extensible Authentication Protocol $($EAP$)$