According to the requirements (first use TACACS+, then allow login with no authentication), we
have to use "aaa authentication login ... group tacacs+ none" for AAA command.
The next thing to check is the if the "aaa authentication login default" or "aaa authentication
login list-name" is used. The 'default' keyword means we want to apply for all login connections
(such as tty, vty, console and aux). If we use this keyword, we don't need to configure anything
else under tty, vty and aux lines. If we don't use this keyword then we have to specify which
line(s) we want to apply the authentication feature.
From above information, we can find out answer 'R1#sh run | include aaa
aaa new-model
aaa authentication login default group tacacs+ none
aaa session-id common
R1#sh run | section vty
line vty 0 4
password 7 0202039485748
If you want to learn more about AAA configuration, please read our AAA TACACS+ and RADIUS
Tutorial - Part 2.
For your information, answer 'R1#sh run | include aaa
aaa new-model
aaa authentication login telnet group tacacs+ none
aaa session-id common
R1#sh run | section vty
line vty 0 4
R1#sh run | include username
R1#' would be correct if we add the following command under vty line ("line vty 0 4"): "login
authentication telnet" ("telnet" is the name of the AAA list above)

RSSI, or "Received Signal Strength Indicator," is a measurement of how well your device can hear a signal from an access point or router. It's a value that is useful for determining if you have enough signal to get a good wireless connection.
This value is measured in decibels (dBm) from 0 (zero) to -120 (minus 120). The closer to 0 (zero) the stronger the signal is which means it's better, typically voice networks require a -65db or better signal level while a data network needs -80db or better.