Why does a price floor lead to surpluses?  Why does a price ceiling lead to shortages?  

Shortage: there is more demand than there is at the equilibrium price. There is also less supply than there is at the equilibrium price, thus there is more quantity demanded than quantity supplied.

Your pretty much short in supply and cant fulfill the demand

While surplus

When a price floor is set above the equilibrium price, quantity supplied will exceed quantity demanded, and excess supply or surpluses will result.

Theirs a a large amount of supply due to the pricing most likely beign high

Explanation:

the first successful, urban blues recording, selling more than 75,000 copies, was made in year 1920.

mamie smith recorded the first commercially successful example of the urban blues,   with the recording of “crazy blues”."crazy blues" was recorded on august 10, 1920, in new york city. within a month of the release of “crazy blues” it had sold 75,000 copies.

b is the correct answer