instruction:
You are given a question or fill-in-the-blank question, two answer options (Option1 and Option2) and an Explanation. Your task is to find the correct answer (return the string of the correct option, not option1/2) for the given question from the given options and using explanation.
question:
Question: What will happen to the levels of pollution on Earth if the population increases? 
 Option1: they will rise 
 Option2: they will fall 
 Explanation: For example, more people on the Earth means more people contributing to global warming and pollution.
answer:
they will rise


question:
Question: If Jim decreases the size of his base, what will happen to the rate of hydroxide ion production? 
 Option1: increase 
 Option2: decrease 
 Explanation: A stronger base produces more hydroxide ions than a weaker base.
answer:
decrease


question:
Question: What is the gravitational effect on an object that is far from Earth by Earth? 
 Option1: high 
 Option2: low 
 Explanation: The gravitational force between two objects decreases as the objects move further apart.
answer:

low