The correct answer is B) come up to speed very slowly and maintain a "safe speed". When towing a disabled vessel, it is crucial to proceed at a "safe speed" to avoid excessive strain on the towing line and potentially damaging the towed vessel. Coming up to speed quickly, as in option A, can create dangerous shock loads on the towing line. Exceeding bare steerageway, as in option C, may not provide adequate control over the tow. Taking a strain as soon as possible, as in option D, can also lead to excessive line tension. The proper procedure is to come up to speed very slowly and maintain a safe, controlled speed throughout the transit, as described in option B.