The correct answer is B) "Slack away". The firing of a red star signal is a distress signal used to indicate that a vessel or person is in grave and imminent danger and requires immediate assistance. According to the Coast Guard regulations, a red star signal means "Slack away" - this signals the launching of a rescue boat or lifeboat to provide assistance to the distressed vessel or person. The other answer choices are incorrect because they do not accurately reflect the meaning of a red star distress signal. Option A is incorrect as it describes a general acknowledgment of being seen, but does not indicate the need for immediate assistance. Options C and D are unrelated to the meaning of a red star distress signal.