GDP is defined as the a. value of all goods and services produced within a country in a given period of time. b. value of all goods and services produced by the citizens of a country, regardless of where they are living, in a given period of time. c. value of all final goods and services produced within a country in a given period of time. d. value of all final goods and services produced by the citizens of a country, regardless of where they are living, in a given period of time.