title: Author's reply.
authors.affiliation: Department of Community Medicine, R. G. Kar Medical College and Hospital, 1 Kshudiram Bose Sarani, Kolkata, India E-mail: drabhijit71@gmail.com.
authors.forename: Abhijt
authors.initials: A
authors.lastname: Mukherjee
authors.forename: Parthasarathi
authors.initials: P
authors.lastname: Bhattacharyya
authors.forename: Indranil
authors.initials: I
authors.lastname: Saha
authors.forename: Rantu
authors.initials: R
authors.lastname: Paul