For each of the following studies, i. state whether the study is a survey, a prospective study, or a retrospective study; ii. state whether the study is comparative or descriptive; iii. if the study is comparative, identify the response and explanatory variable(s). a. A sample of members listed in the directory from a professional organization is used to estimate the proportion of female members. b. To assess the effect of smoking during pregnancy on premature delivery, mothers of preterm infants are matched by age and number of previous pregnancies to mothers of full term infants and then both are asked about their smoking habits during pregnancy. c. A sociologist interviews juvenile offenders to find out what proportion live in foster care. d. A marketing study uses the registration card mailed back to the company following the purchase of a video game to gauge the percentage of purchasers who learned about the purchased game from advertising on facebook, television, or by word of mouth.