The candidate was running for office on a strong platform, confidant that his policies would bring about meaningful change in the constituency.

In the following sentence, four words have been highlighted which may be misspelt or inappropriate in their usage. Mark the erroneous word as the answer and if all the words are correct in their spellings and usage, choose ‘All are correct’ as the correct answer.

The correct option/answer is confidant.

Step-by-step Explanation:

1. Analyze the sentence context:
The given sentence is: "The candidate was running for office on a strong platform, confidant that his policies would bring about meaningful change in the constituency."

2. Identify the meaning of the highlighted words:
- running: Used correctly in context ("running for office" means competing for an elected position).
- strong: Used correctly to describe the candidate's platform.
- confidant: A noun meaning a person with whom one shares a secret or private matter, trusting them not to repeat it to others (e.g., "She is my close confidant").
- constituency: Used correctly to refer to the body of voters in a specified area who elect a representative.

3. Detect the error:
In the context of the sentence, an adjective is required to describe how the candidate felt ("feeling or showing certainty about something"). The correct word is confident (adjective), not confidant (noun).

4. Conclusion:
Therefore, the word confidant is misused in this context and represents the erroneous word in the sentence.