You are correct, the answer is A) behind the lead tug. When tandem tug towing, the more powerful tug should be positioned behind the lead tug. This configuration provides better control and stability, as the more powerful tug can better assist and support the lead tug, especially in adverse weather or sea conditions. The more powerful tug is able to apply additional force and control to the overall towing operation. The other options are incorrect because: B) towing at a right angle is an unsafe and unstable configuration, C) the more powerful tug should not be the lead tug as it would be more difficult to control, and D) the more powerful tug should not necessarily be towing at a faster speed, as this could create tension and instability in the towing arrangement.