List-I shows four configurations made of straight and semi-circular narrow tubes containing air. A sound wave of wavelength \( \lambda = 0.29 \, \text{m} \) enters these structures at the point \( S \) and a sound detector is placed at \( D \). Between the points \( S \) and \( D \), the sound travels only through the tubes. List-II contains the possible smallest values of \( l \) (refer to the figures) for which the detector \( D \) records maximum amplitude. Ignore effects of sharp corners. [Given \( \cos(15^\circ) = 0.97 \)]
Choose the option that best describes the match between the entries in List-I to those in List-II.
