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.
\[
[\text{Given: }\cos15^\circ=0.97]
\]
