Under the Inland Navigation Rules, a pushing vessel and a vessel being pushed ahead are rigidly connected in a composite unit. Which fog signal applies to this composite unit in restricted visibility?

1. A. One prolonged followed by two short blasts at intervals of not more than 2 minutes, as a vessel restricted in ability to maneuver
2. ✓ One prolonged blast at intervals of not more than 2 minutes if making way, or two prolonged blasts if stopped and making no way, as a power-driven vesselCorrect
3. C. One prolonged followed by three short blasts at intervals of not more than 2 minutes, as the last vessel of a tow
4. D. Four short blasts at intervals of not more than 2 minutes, as a pilot vessel