If your vessel were proceeding up river (ascending), the port side of the channel would be marked according to the U. S. Aids to Navigation System on the Western Rivers by __________.

Correct Answer: Option A — green can buoys

When ascending a Western River, the port side of the vessel aligns with the right descending bank. Under 33 CFR 62.51, this side is marked by green can buoys, following the standard "red right returning" convention for upstream transit.