We have been given that we can choose 1 of 4 country CDs, 1 of 3 soul CDs, or 1 of 5 pop CDs.
We need to figure out number of ways in which we can choose 1 CD of each kind from available options.
To figure out number of ways in which we can choose 1 CD of each kind we will use combinations.
First of all we will figure out number of ways of choosing 1 CD out of 4 country CDs, then we will figure out number of ways of choosing 1 CD out of 3 soul CDs. We will also determine number of ways of choosing 1 CD out of 5 pop CDs.
Number of ways of choosing 1 CD out of 4 country CDs =

Number of ways of choosing 1 CD out of 3 soul CDs =

Number of ways of choosing 1 CD out of 5 pop CDs =

Therefore total number of ways to select 1 CD is 