Which of the following are considered general difficulties in measuring demographic information? Choose one best answer. a. Age can be defined or conceptualized differently in different regions or cultures. b. Defens ut re and tie characterotic are not consitent over time or space (eg. the definion can be diferent a. O c. Migration is difficult to define (e.g. how far must one move to be considered a migrant?). d. Data collection at a national scale can be costly and time consuming. Oe. All of the above present difficulties in measuring demographic information