Given the task definition and input, reply with output. You are given a short paragraph, a question and two choices to answer from. Choose the correct answer based on the paragraph and write the answer(not the key).

Paragraph: Low food supply or a lack of space can lower birth rates, increase death rates, or lead to emigration.
 Question: A population of squirrels in a local forest had less food available to them this spring than they did last spring. During which spring will more squirrels leave the area to live somewhere else? 
 Choices: A)this spring 
B)last spring
this spring