Match the instrument with its classification group
a. guitar idiophone
b. guiro aerophone
c. bass drum chordophone
d. bass clarinet membranophone

The guitar is a chordophone, the guiro is an idiophone, the bass clarinet is an aerophone, and the bass drum is a membranophone. The chordophone, idiophone, aerophone, and membranophone are the types of musical instrument differed by the source of the musical sound. The chordophone uses strings as the source of its sound. The aerophone uses air as the source of its sound. The idiophone uses its body's vibration as the source of its sound and the membranophone uses a layer of leather as the source of its sound.

The correct answer is b, social stratification is needed for a society to exist. marxist theory regarding social stratification is that due to the differing economic capacities among people in society, a natural separation occurs between those that own the means of production and those that sell their labour in the production chain.