Read and complete the sentence with the correct part.

One day, a group of young people came to me and said that they had something to say. I was very surprised. They said that they were all grateful for the changes I brought into their lives through peer education. I was so happy to hear this. It aroused joy in my heart. This experience made me understand that only volunteer work could have such a profound impact on people’s lives.

The pronoun this in “I was so happy to hear this …” refers to the …

• young men’s gratitude.
• advice on how to change her life.
• surprising information.
• offer to study together.