What is the purpose of a forgery? O A. To reproduce a work of art that is too fragile to be restored
properly
B. To satirize a work of art by using elements of that work in an
absurd way
C. To make buyers believe they are getting an original work of art
D. To allow new artists to establish a reputation among buyers

pitch- the definition of pitch is as follows:

"the quality of a sound governed by the rate of vibrations producing it; the degree of highness or lowness of a tone."

it seems to me that yes they solo on the chord changes.  coltrane for sure solos on the chord changes. instead of changing scales, they use a different method over the chord changes. this melody is very  unique but may often times even be considered simple, which is quite common in this modal  type. for example, there are changes from the key of minor to major in this piece, which makes it  unique in its own way.