The correct answer is 'repulsive.' - Let us see the meaning of attractive: - Attractive: appealing to look at; alluring, pleasant, acceptable. - Example: He is a stunningly attractive and charismatic man. - Let us see the meanings of the given options: - Unnatural: contrary to the ordinary course of nature; abnormal. - Modern: relating to the present or recent times as opposed to the remote past. - Repulsive: extremely unpleasant or unacceptable. - Disapproving: expressing an unfavourable opinion. - From the meanings of the given words, we can say that the word 'repulsive' is the opposite of the meaning of the underlined word 'attractive'. - Hence, the correct answer is 'repulsive.'