Refer to the exhibit.
A network technician is unable to ping from R1 to R2.
What will help correct the problem?
A . Ensure that the serial cable is correctly plugged in to the interfaces.
B . Apply the clock rate 56000 configuration command to the serial0/1 interface of R1.
C . Configure the serial0/1 interfaces on R1 and R2 with the no shutdown command.
D . Change the address of the serial0/1 interface of R1 to 192.1.1.4.
E . Change the subnet masks of both interfaces to 255.255.255.240.
Answer: A