In which of the following prozone phenomenon is most evident

The reagin antibody becomes detectable 7-10 days after the appearance of the primary chancre. Sensitivity in the primary chancre is 60-75%, with the titer being low, up to eight. In secondary syphilis, sensitivity is 100% and titers range from 10 to 128 or more. The prozone phenomenon may be a problem in high titer sera and it is, therefore, essential to test sera in dilutions. Ref: Textbook of microbiology; Ananthanarayan and paniker's; 10th edition; Pg: 381