A. On that Saturday Sarah planned --- 1) to visit the pet shelter 2) to meet her friends at the park 3) to explore a new neighborhood 4) to volunteer at a local charity

This question asks about Sarah's plan for Saturday based on the text. The text states: "Now, Sarah left with a strong intention to persuade her parents to adopt the dog. Besides, she made up her mind to volunteer at the shelter, helping out wherever she could and giving those animals the love they deserved." This directly indicates her plan to volunteer.

Answer: 4) to volunteer at a local charity