Question 361Navigation General

The correct answer is A) A and D. The two shapes used to indicate a preferred channel in illustration D045NG are the triangle (A) and the diamond (D). This is based on the regulations and conventions for navigational aids and channel markers used by the US Coast Guard. The triangle shape is used to mark the preferred side of a channel, while the diamond shape indicates the preferred channel itself. The other options, B and C, represent different navigational markers that are not used to indicate a preferred channel.