Refer to the exhibit. R1 is performing mutual redistribution, but OSPF routes from R3 are unable to reach R2. Which three options are possible reasons for this behavior? (Choose three.)
A. R1 requires a seed metric to redistribute RIP.
B. The RIP version supports only classful subnet masks.
C. R1 is filtering OSPF routes when redistributing into RIP.
D. R3 and R1 have the same router ID.
E. R1 and R3 have an MTU mismatch.
F. R2 is configured to offset OSPF routes with a metric of 16.
except by B, all other options are valid reasons IMHO