As a US citizen working in the US for a Chinese company your wages are subject to social security and medicare tax. The employer should have withheld those taxes per IRS instructions. China is not on the Totalization Agreement list.
If you have a W2 then "None of the above" would apply. If not, you may be using the option "Substitute form".
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
