Explanation:

- Anxious: This word describes a state of worry or nervousness. It doesn't capture the concept of becoming strong despite difficulties.

- Triggered: This term usually refers to reacting emotionally, often due to a traumatic experience. It doesn't fit the idea of growing stronger through challenges.

- Safe: While this word means free from harm or risk, it doesn't describe the process of becoming strong after facing hardships.

- Resilient: This is the correct choice. It means having the ability to recover quickly from difficulties. It describes the process of growing stronger owing to challenges.