Question

if you encounter a red and green marker when proceeding in the upstream (returning from sea) direction what must you do?
a you must keep the marker on your starboard (right) side
b you must keep the marker on your port (left) side
c you may pass on either side of the marker
d turn around; you may not proceed any further

Explanation:

A red and green marker is a junction marker. When proceeding upstream (returning from sea), junction markers allow vessels to pass on either side. This is a standard rule in maritime navigation to indicate that the marker is at a point where the channel splits or joins, and vessels have the option to choose either side to continue their journey.

Answer:

C. You may pass on either side of the marker