A cross-sectional study was conducted on the association between passive smoke inhalation and the occurrence of dental caries in children. (Passive smoke exposure occurs when children live with family members who smoke). The investigators thought that conclusions from this study were limited because of the cross-sectional nature of the data. Suppose that they asked you for advice and you told them that they should have conducted a prospective cohort study because it is a better study design. Which type of cohort is the best for this situation?A. Special cohortB. Case cohortC. General cohortD. Experimental cohort