Which statement is correct regarding the steps taken to reduce global warming?
I. Cleaning up and gasification of coal (for which technology is available) will result in lesser pollution.
II. Increased use of natural gas contains only half of the carbon and no Sulphur.
III. Renewable energy sources, such as wind, solar, photo-voltaic and fuel cells, tidal, etc.
IV. Manufacture of fuel-efficient vehicles.
(a) I & II (b) Only III (c) Only II (d) All the above