Final answer:
The Scatchard plot for n-equivalent binding sites is a straight line with a negative slope, allowing determination of binding affinity and number of sites.
Step-by-step explanation:
The Scatchard plot is a graphical representation used in biochemistry to analyze binding sites and their interactions with ligands. When dealing with n-equivalent binding sites, where all sites have the same affinity for the ligand and do not interact with each other, the representation on a Scatchard plot is a straight line with a negative slope. A Scatchard plot is derived from a hyperbolic binding curve, and it allows the determination of both the binding affinity and the number of binding sites. Therefore, the correct answer to the question is:
a) A straight line with a negative slope.