A subscriber complains that his DSL rates are slower than the service he
ordered. The customer ordered ADSL at 1 mpbs downstream and 256 kbps upstream, but the maximum bitrate observed during file downloads is 100 kbps downstream. Of the following four choices, which is clearly the most appropriate information needed to begin troubleshooting the problem?

A.
The software version running in the DSLAM

B.
The FEC parameters for the subscriber’s ADSL port in the DSLAM

C.
The actual DSL rate that is reported when the DSL line is trained

D.
The manufacturer and model of ADSL CPE that is used