Answer:
The sentence from the paragraph that is the topic sentence is 3.By collecting, cleaning, and distributing thousands of pairs of gently used athletic shoes Give Running makes a difference for children in need, including some who have never owned athletic shoes of any kind.
Explanation:
A topic sentence covers two functions, it gives you a general idea of what is the writer going to talk about and it has a controlling idea that helps to keep focus on the topic, this sentence summarizes the topic of all the extract which is about people in need and about how they receive shoes from charity. The controlling idea keeps in mind that it is specifically for children in need