Rules of the Road: BOTH INTERNATIONAL & INLAND The tug shown in illustration D024RR below is greate...

figured it out

I would like to know too why A is not the answer..

It's because the towing vessel is greater than 50 meters. It will need a second masthead light "abaft of and higher than the forward one".

Here is the break down of rules/confusion...

Rule 23(a)(ii) lights required for power driven vessels underway says the vessel needs a second masthead light because its greater than 50 meters.. But then Rule 24(a)(i) lights required for towing/pushing says: "Instead of the light prescribed in Rule 23(a)(i) or 23(a)(ii), two masthead lights in a vertical line." THEN there is Rule 24(d) "A power-driven vessel to which Rule 24(a) or (c) applies shall also comply with Rule 23(a)(i) and 23(a)(ii)"

None of the above is the answer because the towing vessel won't have a towing light, the last vessel being towed will for visibility purposes.

I guessed "A". After further review believe "D" is correct because towing vessel would show only "1" towing light (yellow) above the stern light when towing astern.

Here's why they are ALL Wrong:
A): 3 white Masthead lights would be "International only", Greater than 50 meters would require an "After Masthead" light. 2 towing lights is "Inland Only" when pushing ahead or tied alongside.
You see where this is going?
Right answer: Three Masthead lights, Second/Aftermasthead light, Red White Red vertical lights, Stern light, Towing light, Side lights, and don't get me started on shapes and lights for the towed vessels.

3 masthead lights for 65 meter towing vessel.

Rule 24(d) A power-driven vessel to which paragraph (a) or (c) of this Rule applies shal also comply with Rule 23(a)(ii).

Simply put because the vessel is over 50 meters in length it is required to have a second masthead light abaft of and higher than the forward on.

They tricked us on this one.

Rule 27 (c)