As Shown Below,a Garden Room Has Three Walls,a Floor and a Roof,but

Multiple Choice

As shown below,a garden room has three walls,a floor and a roof,but is open to the garden on one side.The wall widths are L and w.The roof height is h.When traveling sound waves enter the room,standing sound waves can be present in the room if the wavelength of the standing waves is

A) $\frac { 2 L } { n }$ ,where n is a positive integer.
B) $\frac { 4 w } { n }$ ,where n is an odd integer.
C) $\frac { h } { n }$ ,where n is an even integer.
D) in all cases listed above.
E) given by (a) or (b) above,but not by (c) .