Salts, sulphur and potash industries are which kind of industry ?

Chemical based Industries

The correct answer is option 3: Chemical based Industries

Chemical based Industries: Such industries use natural chemical minerals, e.g. mineral-oil (petroleum) is used in petro chemical industry. Salts, sulphur and potash industries also use natural minerals. Chemical industries are also based on raw materials obtained from wood and coal. Synthetic fibre, plastic, etc. are other examples of chemical based industries.