“To end in smoke” means:

The correct answer is To fail completely. The idiom \"to end in smoke\" means that a plan, effort, or project comes to nothing, fails completely, or produces no useful result. It describes situations where expectations are not fulfilled and all efforts are wasted.

• To fail completely – Correct. The plan or effort produces no successful outcome.
• To make completely understand – Incorrect. This is unrelated to the idiom.
• To excite great applause – Incorrect. This refers to receiving praise or appreciation.
• To overcome someone – Incorrect. This means to defeat or conquer a person.

Example: Despite months of planning, the business proposal ended in smoke because investors refused to fund the project.