Refer to the exhibit.
Referring to the exhibit, what are two reasons why R2 and R4 show a different hello interval than R1 and R3? (Choose two.)
A. R4 is the DIS.
B. R2 is the DIS.
C. R4 has explicit configuration to set the hello interval to 3 seconds.
D. R2 has explicit configuration to set the hello interval to 3 seconds.