Which two features protect the ERX Edge Router from denial-of-service attacks?()<br /> <img src="https://nimg.ppkao.com/2018-08/gelingxia/2018080817105993061.jpg?sign=e1192b1e72c4af17e21d860801e039bf&t=62d1756d" />
A、A
B、B
C、C
D、D
A、A
B、B
C、C
D、D
A、rate limiting of ICMP B、RADIUS authorizations C、source address validation D、stateful firewall on the router