The correct answer is B) 2, which indicates the frapping line in the illustration D016SA. The frapping line is a line used to secure a bight or loop in a larger rope, such as a mooring line or anchor rode. In the illustration, the number 2 is clearly pointing to the frapping line, which is used to tighten and secure the larger rope. The other answer choices are incorrect because they do not correspond to the frapping line in the illustration. Option A (1) likely refers to the larger rope or line, option C (3) may refer to another component of the rigging, and option D (4) does not appear to indicate any relevant feature in the image.