In the topology shown in the figure, configuration needs to be done on the RTA to import the default route in the OSPF area.

Which of the following configurations can achieve the above goals?

In the topology shown in the figure, the following configurations are performed on RTA, RTB, RTC and RTD respectively:
RTA-LoopBack0] ip address 1.1.1.1 255.255.255.255
RTA]ospf 1
RTA-ospf-1]area 1
RTA-ospf-1-area-0.0.0.1]network 10.0.0.0 0.0.0.255
RTA-ospf-1]import-route direct
RTB-LoopBack0] ip address 2.2.2.2 255.255.255.255
RTB]ospf 1
RTB-ospf-1]area 1
rtb-ospf-1-area-0.0.0.1]network 10.0.0.0 0.0.0.255
RTB-ospf-1-area-0.0.0.1]area 0
rtb-ospf-1-area-0.0.0.0]network 2.2.2.2 0.0.0.0
RTB-ospf-1-area-0.0.0.0]network 20.0.0.0 0.0.0.255
RTC-LoopBack0] ip address 3.3.3.3 255.255.255.255
rtc]ospf 1
RTC-ospf-1]area 0
RTC-ospf-1-area-0.0.0.0]network 20.0.0.0 0.0.0.255
rtc-ospf-1-area-0.0.0.0]area 2
RTC-ospf-1-area-0.0.0.2]nssa default-route-advertise no-summarRTC-ospf-1-area-0.0.0.2]network
30.0.0.0 0.0.0.255
RTC-ospf-1]import-route direct
RTD-LoopBack0] ip address 4.4.4.4 255.255.255.255
RTD]ospf 1
RTD-ospf-1]area 2
RTD-ospf-1-area-0.0.0.2]network 30.0.0.0 0.0.0.255
rtd-ospf-1-area-0.0.0.2]nssa
RTD-ospf-1]import-route direct
Which of the following routes may exist in the RTD's routing table _______.

About the difference between system policy routing and interface policy routing. The correct statement is _________

For the NSEL field in the NSAP address, the following description is correct ________.

Which of the following descriptions about routing filtering are correct?