C.The polymerization for the production of the above random copolymers is usually carried out in a hydrocarbon solvent.Examples of the above hydrocarbon solvent are aliphatic hydrocarbons such as hexane, heptane, octane and kerosine; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and aromatic hydrocarbons such as benzene, toluene and xylene.