LLC, multi member to single member

My deceased husband was a member of our llc.  I filed our last multimember return for 2021.  I checked the box for the last k1 issued to him.

This year I am told I need to complete a schedule C.  That doesnt fit  a rental real estate business.  A schedule E fits that.  I do not sell any product, i simply run a real estate rental of owned property.  I am confused about the schedule C.