c. stays the same
d. is impossible to determine. (The thermal expansion of the pipe is negligible.)
Outdoor pipe organ is a musical instrument that is used to play music. It produces some soothing notes and is very peaceful to the ears. The organ pipe is the source of sound for the outdoor organ. And the length of the pipe determines the wavelength of the sound. When the air temperature of the surrounding is increased, the fundamental frequency of one of the organ pipes will be increased as the speed of the sound will increased.