Which of the following descriptions about pointer adjustment is correct ？

Which of the following descriptions about pointer adjustment is correct ？
A . When the rate of VC4 (frame rate) is higher than that of AU-4 (frame rate), it will be adjusted
B . If the station detects that there is a low-level channel with a TU pointer adjustment event, it means that the station has a pointer adjustment
C . AU and TU pointer adjustments are adjusted in units of 1 byte
D . When the receiving end receives NDF inversion for 8 consecutive frames, the device generates an AU_LOP alarm (AU pointer is lost)

Answer: D