Explanation:

Recently, the Indian Institute of Technology (IIT), Guwahati, has developed a super-hydrophobic cotton composite with Metal-Organic Framework (MOF) that can clean-up marine oil-spill.

• It is a novel MOF composite, which is a highly porous and water-repellent material and can absorb oil selectively from an oil-water mixture.
• This MOF composite has great capability for selective separation of the oils from oil/water mixtures and the separation efficiency lies between 95% and 98%, irrespective of the chemical composition and density of the oils.
• It can also absorb large volumes of oils and can be reused for a minimum of 10 times so that the sorbents can provide more recovery of the spilled oil.
• It will clean-up the spilled oil from environmental water (river, sea or ocean water) during oil transportation with high efficiency and large absorption capacity, thus reducing environmental water pollution.
• It is environmentally friendly and cost effective.

Hence option 3rd is correct.