Option 4 is the correct response, signifying that neither statement 1 nor statement 2 is accurate.

Statement 1 asserts that between the census years of 1951 and 2001, India`s population density tripled. This is incorrect as although there was a significant increase in population density, it was less than three times.

Statement 2, on the other hand, asserts that the annual growth rate of India`s population doubled between the census years of 1951 and 2001. However, this is not true as the growth rate did not double; in fact, it decreased marginally over this time period.

Therefore, both these statements are incorrect, making option 4 the correct answer.