You need an iso harness. You can get an iso a/b harness here:
https://a.co/d/fe8bOdo
c (yellow) is part of a mini iso cde combo plug. C and D are 6 way plugs. E is an 8 way plug. Here is a link for a c plug
https://camaudiotech.com/product/m-44-car-radio-yellow-mini-iso-housing-6-way-car-audio-connector-with-pins/
I think these are available in other places. ISO plugs are standard so you just need to know what to search for. Also here
https://www.aliexpress.com/i/3256804978016453.html