C+ and B- may not qualify for automatic standard admission. BUT on the right side of the same web page, it says admissions committee will review other non-academic things in their admission consideration, if application does not meet automatic admission. Strong leadership may help.
Copied from IU site.
“If your application does not meet automatic admission criteria, the admissions committee will review all other materials provided in your application, including but not limited to: extracurricular activities, community service and any work experience. Academic performance will weigh most heavily in the decision.”
https://kelley.iu.edu/programs/undergrad/admissions/current-iu.cshtml