What security risk exists with SNMPv1/v2c community strings, and what is the recommended SNMP version that eliminates this risk?

• A.SNMP community strings are only a risk on UDP; switching SNMP to TCP in SNMPv2c prevents interception
• B.SNMP community strings are encrypted with AES-128 in SNMPv2c; the risk is that they can be brute-forced due to short key length
• C.SNMPv1/v2c community strings are transmitted in cleartext (no encryption); an attacker capturing network traffic (passive sniffing) can read the community string and use it to query (read community) or modify (write community) network device configurations. 'public' and 'private' are default community strings that many devices ship with enabled. SNMPv3 eliminates this risk with authentication (MD5/SHA HMAC) and encryption (DES/AES) for all SNMP messages
• D.SNMPv2c community string risk is that they expire after 30 days; devices become unmanageable if strings are not rotated