The correct answer is 'natural.' Key Points - Let us see the meaning of Organic: - Organic: not using artificial chemicals in the production of plants and animals for food, natural. - Example: The illness is organic in origin. - Let us see the meanings of the given options: - Natural: as found in nature and not involving anything made or done by people, organic. - Speedy: done or occurring quickly. - Unusual: not habitually or commonly occurring or done. - Disciplined: showing a controlled form of behaviour or wayof working. - From the meanings of the given words, we can say that the word 'natural' is nearest in meaning to the underlined word 'organic'. - Hence, the correct answer is 'natural.'