How would each secured party would properly perfect his or her security interest in the following situations:

a. Matt is a manufacturer of refrigerators. John, a retailer, buys a number of these refrigerators, John signs a security agreement giving Matt a security interest in the refrigerators.

b. Mike sells a refrigerator to Ruby, to be used in Ruby’s home. Ruby signs a security agreement giving Mike a security interest in the refrigerator.

c. Mike sells a refrigerator to Dr. Shaw to be used in his office to store medicines. Dr. Shaw signs a security agreement giving Mike a security interest in the refrigerator.

d. Mike sells a refrigerator to farmer Jake, who needs it to store eggs not sold at the market. Jake signs a security agreement giving Mike a security interest in the refrigerator.