The correct answer is C) running fixes are better estimates of true position than dead-reckoning positions. The position labeled "C" on the illustration was plotted using a running fix, which provides a more accurate estimate of the vessel's true position compared to a dead-reckoning position. Running fixes incorporate multiple observations, such as bearings or ranges, to triangulate the vessel's location, whereas dead-reckoning positions are calculated based solely on the vessel's course and speed. Running fixes account for the effects of current, wind, and other factors that can cause the vessel to deviate from its expected path, making them a more reliable indicator of the vessel's actual position. The other answer choices (A and B) are incorrect because they do not directly explain why the position labeled "C" was plotted, as they do not relate to the use of running fixes versus dead-reckoning positions.