appropriate option that can substitute the underlined word in the given sentence.- The dedicated teacher laboured assiduously to aid her pupils in achieving success.

Explanation:

The underlined word “assiduously” means:
👉 working very hard, diligently, and with great dedication

So, we need a word that shows strong dedication and effort.

✔️ Committed fits best because it means:
👉 devoted, dedicated, fully involved in a task

❌ Option Analysis:

• Un-biased → neutral, not related to hard work ❌
• Uninvolved → not taking part ❌
• Apathetic → showing no interest ❌
• Committed → ✔️ dedicated and hardworking