Schedule c line b what goes in this line

The Business Code is a 6 digit number for your activity.  Here are the IRS instructions for Schedule C.  Business codes start on page 17.  
http://www.irs.gov/pub/irs-pdf/i1040sc.pdf

See the FAQ on Business Codes,
https://ttlc.intuit.com/questions/1899356

Thanks so much. I was really stuck.