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Which among the following statement/s is/are always TRUE about inflection points? 1. The concavity of a function changes at this point. 11. The slope of the tangent line at this point is zero. Ill. It defines whether or not an extremum point is global or local. IV. For a continuous function that does not pass the horizontal line test, the number of inflection points is N - 1, where N is the number of extremum points. O I & III OI & IV O I & 1I O III & IV O II & 111 O II & IV