A tech company launches a new Applicant Tracking System $($ATS$)$ designed to prioritize candidates with top$-$tier university degrees and at least five years of experience in similar roles. Over the next $12$ months, diversity among new hires plummets, and innovation metrics decline sharply across departments. What is the most strategic corrective measure for the HR department to implement?

Select one:a$.$ Broaden ATS filters to prioritize experiential competencies and transferable skills rather than degree pedigree and direct role experience.b$.$ Remove degree requirements from all job postings to avoid bias and increase candidate volume.c$.$ Retain ATS filtering criteria but add mandatory diversity quotas to meet innovation targets.d$.$ Shift hiring focus entirely toward external agencies specializing in underrepresented talent pipelines.