Concept:"Indolence" is a noun that means laziness, so its opposite must express hard work or industriousness.
Explanation:The underlined word "indolence" describes a state of being habitually idle or unwilling to work.
A person who shows indolence avoids effort and prefers to do nothing.
Now examine each option to find the opposite meaning.
Option A, "indulgence," refers to allowing oneself excessive pleasures, which is not the opposite of laziness.
Option B, "laziness," is actually a synonym of indolence, not an antonym.
Option D, "prudence," means exercising care and good judgment, which does not contrast directly with indolence.
Option C, "diligence," means showing steady, careful, and persistent effort in one's work.
A diligent person works hard and stays industrious, which is the direct opposite of being indolent.
Therefore, the word opposite in meaning to "indolence" is diligence.
Answer:C. diligence