As part of a data base on new births at a hospital some variables recorded are the age of the mother, marital status of the mother (single, married, divorced, other), weight of the baby, and sex of the baby. Of these variables
(a) age, marital status, and weight are quantitative variables.
(b) age and weight are categorical variables.
(c) sex and marital status are categorical variables.
(d) sex, marital status, and age are categorical variables.