Explanation:

- In December 2018, Joshna Chinappa won the Women's Singles title at the National Squash Championship in Delhi.

- Bhuvaneshwari Kumari is a former Indian squash player known for her achievements in the 1970s and 1980s, but she did not compete for this title in 2018.

- Sachika Balvani is an emerging squash player, but she did not win the championship in that year.

- Aparajitha Balamurukan is another Indian squash player; however, she was not the winner in 2018.

Correct Answer: Joshna Chinappa