The answer to your question would be that the definition that best identifies and explains the function of the word "tying" as it is used in this sentence is the following one: In the selected sentence, the word "tying" is a verbal that functions as an adverb.
A verbal is a word formed from a verb but functioning as a different part of speech. "Tying his shoe" is a participle phrase. In fact, it is present participle phrase, as it is created from the form of a verb used with the verb to be as an auxiliary verb (progressive tense). Removing the auxiliary verb and using the -ing form of the main verb produces a present participle. In this case the participle is functioning as an adverb because it is telling something about the manner in which Garrett prevented an embarrassing fall. He did this tying his shoe. You can tell this by asking the following question: How did Garrett prevent the embarrassing fall? Tying his shoe.
Answer:
I believe the correct answer is: his
Are there options, I assumed there would be since you used the word "which".
1. Meaningful parts means words that make sense; words you can understand. Flagpole would become flag and pole.
2. What does flag mean? A piece of cloth, usually rectangular, of distinctive color and design, used as a symbol, standard, signal, or emblem. What does pole mean? A long, cylindrical, often slender piece of wood, metal, etc.
3. A symbolic cloth on a pole, or meant to be on a pole, would be called flagpole.
4. Use these steps and summarize them in your own words.
Hope this helps!