The answer is a - Dye binding method.

The dye binding method is a quantitative measurement of protein in urine. It uses a colorimetric assay that measures the amount of protein in urine by binding the protein to a dye and measuring the absorbance of light at a specific wavelength. The amount of protein in the urine is then calculated based on the absorbance reading.

One example of a dye binding method is the biuret method, which uses copper ions to bind with the protein in urine and form a complex that absorbs light at a specific wavelength. The amount of protein in the urine is then calculated based on the absorbance reading.

References:

1. Tietz NW, ed. Fundamentals of Clinical Chemistry. 5th ed. Philadelphia: W.B. Saunders Company; 2001.

2. Burtis CA, Ashwood ER, Bruns DE, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 5th ed. St. Louis, MO: Elsevier Saunders; 2012.