Which is the correct option to complete the text below?

Major Current Environmental Problems

Ocean Acidification: It is a direct impact of excessive production of C02. 25% of CO2 is produced by humans. The ocean acidity has increased by the last 250 years, but by 2100, it shoot up by 150%.

Acid Rain: Acid rain occurs due to the presence of certain pollutants in the atmosphere. Acid rain is a known environmental problem that have serious effect on human health, wildlife and aquatic species.

(Adapted from http://www.conserve-energy-future.com)