Index funds ARE inherently diversified because they invest in all securities constituting a particular index, which typically includes 30-50 different stocks (e.g., Nifty has 50 stocks). Saying index funds are 'not diversified' is factually incorrect. The other statements about index funds - that they invest in index shares, in the same proportion as the index, and aim to minimize tracking error - are all true characteristics. Option D correctly identifies the false statement.