The correct answer is C) The plants and animals are harmed.
On burning of fuel in power stations, vehicles, factories emit smoke which contains lots of invisible gases which are invisible. Some of the gases such as nitrogen oxides and sulphur dioxide react with the water droplets in clouds to form sulphuric and nitric acids. The rain from these clouds falls on the Earth as “acid rain". The acid rain is harmful to our environment. It is source of pollution and when it falls it can have a serious effect on soil, trees, animals, buildings and water.