The correct answer to the question is option 1 - Haryana. The sex ratio is a measure of the number of females per 1000 males in a population. According to the 1991 Census in India, Haryana had the lowest sex ratio among all the states.

Option 2 - Sikkim, option 3 - Arunachal Pradesh, and option 4 - Punjab, are not the correct answers as they did not have the lowest sex ratio in India as per the 1991 Census.

Haryana, which is located in northern India, has consistently had one of the lowest sex ratios in the country. A low sex ratio indicates a higher number of males compared to females in the population. This can be due to various factors such as sex-selective practices, female infanticide, and gender-based discrimination.

It is important to address and work towards improving the sex ratio in states like Haryana to ensure gender equality and the well-being of the population.