The source book printed no answer; this one was worked out and checked — see the explanation.
Explanation
A primary (absolute) method gives the amount of analyte from a fully understood measurement relation, without calibration against a reference standard of the same analyte. In isotope-dilution mass spectrometry, a known amount of an isotopically enriched spike is added to the sample. The amount of analyte is then calculated directly from the measured isotope ratio of the blend, so no calibration curve is needed. ICP emission spectrometry, energy-dispersive XRF and anodic stripping voltammetry are relative methods that must be calibrated with reference standards. Answer: (d).