The man is not as powerful as he once was, his influence has considerably …

Analyze the question

The sentence says the man "is not as powerful as he once was," so the blank needs a word meaning his influence has reduced or grown smaller.

Explain the concept

This is a vocabulary-in-context question. The first clause gives the clue, and the missing word must fit both the meaning and the grammar. "Influence" is the subject, so the verb must make sense with an abstract thing like influence. It must also work without a direct object, because nothing follows the blank.

Check each option

• A. toppled: Means to overturn or cause to fall. It is used for governments, leaders or objects ("the regime toppled"), not for influence. It also suggests a sudden collapse, while "considerably" suggests a gradual decline.
• B. quelled: Means to suppress or put an end to something, such as a riot or fear. It is transitive (someone quells something), so it does not fit here.
• C. diminished: Means to become smaller or less. "His influence has considerably diminished" is natural and matches "not as powerful as he once was." It also works without an object.
• D. discarded: Means to throw away. People discard objects, not influence, and the word needs an object.

Answer

The correct option is C. diminished. The sentence becomes: "The man is not as powerful as he once was; his influence has considerably diminished."

Tip

In "best completes the sentence" questions, find the clue in the first part of the sentence (here, "not as powerful as he once was"). Then eliminate words that are the wrong part of speech or need an object that isn't there. "Considerably" often pairs with words of degree like diminished, reduced, improved, increased.