a single-member LLC is disregarded for tax purposes so enter the k-1 as if the LLC didn't exist ie partnership k-1, s-corp k-1, trust/estate k-1. you cannot enter it on schedule C. k-1 instructions in Turbotax say if the partner is a disregarded entity (true) enter the partner's TIN (your LLC's TIN/EIN) and its name. there will be a page that asks for type of partner also check the disregarded entity box so you can enter the TIN and LLC's name
however, I saw that info nowhere on the official forms for filing. It only appears on a worksheet that you keep for your records. it cannot be submitted to the iRS as part of e-file so you would need to mail in your return if you wanted to include that page
