Which of the following descriptions is wrong about how Time delay mode works?

Which of the following descriptions is wrong about how Time delay mode works?
A . From the switching relationship, the access device is in the "active" position in the switching of the Time delay protection group. After detecting the fault of the working port, it immediately starts the switching according to the detection result.
B . The links in the protection group are in traffic load balancing mode
C . After the OLT detects the failure of the working port, it will not immediately switch the service to the protection link.
D . Immediately open the protection port when the access device is switched

Answer: C