Beat Music sells pianos. Its concert piano sells for $180,000, which includes delivery, installation, and a two-year warranty that covers any product defects. In the contract, customers can choose to buy an extended three-year warranty for maintenance and repair at $2,000. Customers also have an option to upgrade plastic keys to bone keys for $10,000. The extended warranty would normally sell for $2,000, and the installation of bone keys has a stand-alone price of $10,000. Given the above, how many performance obligations exist in the contract to purchase a concert piano?

a. 0

b. 1

c. 2

d. 3

e. 4