Among the following statements about traditional variable sampling, the correct one is ().

Analysis of all variable sampling belongs to detail test sampling (A is correct); Non-sampling risk has nothing to do with sampling, and non-sampling risk (B error) can be controlled quantitatively; The test object of variable sampling is quantity, which has nothing to do with deviation rate (C error). Traditional variable sampling belongs to statistical sampling, so random sampling or systematic sampling should be adopted to select samples (D is correct).