Why is the enzyme-linked secondary antibody crucial in the ELISA process?

• A. It catalyzes a reaction that produces a colored product, allowing quantification of the antigen.
• B. It directly binds to the antigen, increasing specificity.
• C. It enhances the binding of the primary antibody to the antigen.
• D. It blocks non-specific sites to prevent false positives.

Answer: (A)