When the ADSL/ADSL2+ line conditions are better, what parameters can be adjusted to increase the transmission rate?

When the ADSL/ADSL2+ line conditions are better, what parameters can be adjusted to increase the transmission rate?
A . Change the port channel mode to "fast"
B . Change the port channel mode to "Interleaving" and increase the interleaving delay
C . Reduce the target noise margin
D . Improve the target noise margin

Answer: AC