If the read community is known and there is SNMP connectivity to a device (without an access-list limiting this):

A.
The System Description (sysDescr), which includes the full name and version identification of the system’s hardware type, software operating-system, and networking software, can be ascertained through and SNMP query.

B.
The entire configuration of the router can be read but not modified.

C.
The passwords on the router can be modified.

D.
The passwords on the router can be read, not modified. This enables the attacker to access the router as a base of operations for other attacks.