d. You’ve designed one of the ranks of pipes within the organ using a metal alloy consisting of a mixture of tin and copper. The customer decides (at the last minute) that they like the sound of stainless steel pipes for these ranks better. How do you anticipate this change in pipe material will impact the sound produced by the organ?

Question

i. The fundamental frequencies will remain unchanged but the harmonics will be different
ii. The fundamental frequencies will be higher while the harmonics will remain unchanged
iii. No change in fundamental or harmonic frequencies

Answer 1

I bet your teacher wants answer iii. However, I also bet he has never heard E. Power Biggs recordings on a series of German organs, of various materials. yes, they sound different.
See this:
http://www.albany.edu/piporg-l/pipemet.html