What is the answer to puzzle 118 in Professor Layton and the Curious Village?

This puzzle is one of the hidden puzzles called not knots. The location is Archibald's and the character is Archibald. The solution for this multiple choice puzzle is c for 50 picarats and a bookcase.

Puzzle 108, Not knots, Curious village.

Answer = The C rope is the only rope that will form a knot.