有关GDP的定义

题目

有关GDP的定义
GDP is defined as the market value of all final goods and services produced
a.x05by the citizens of a country,regardless of where they live,in a given period of time; this definition focuses on GDP as a measure of total income.
b.x05by the citizens of a country,regardless of where they live,in a given period of time; this definition focuses on GDP as a measure of total expenditure.
c.x05within a country in a given period of time; this definition focuses on GDP as a measure of total income.
d.x05within a country in a given period of time; this definition focuses on GDP as a measure of total expenditure.
ANS:D
答案D和C区别在哪里?总收入不是等于总支出么?

答案

c讲的是收入,d讲的是支出,计算GDP有两种方法,一种收入法,一种支出法.两者好像都没有讲到进出口