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.

Q: Question: Sandra sees a tiny glacier, and notes that it has smaller tributary glaciers flowing into it, in valleys that are 
 Option1: shallow 
 Option2: deep 
 Explanation: Smaller tributary glaciers, like tributary streams, flow into the main glacier in their own shallower U-shaped valleys.

A: deep
****
Q: Question: As a boy grows to a man and his larynx grows smaller, his voice gets 
 Option1: deeper 
 Option2: higher. 
 Explanation: The voice becomes deeper as the larynx in the throat grows larger.

A: higher.
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Q: Question: If Milo's country begins decreasing the size of its population, what happens to its growth rate? 
 Option1: it decreases 
 Option2: it increases 
 Explanation: With exponential growth, the population starts out growing slowly. As population size increases, the growth rate also increases.

A:
it decreases
****