Answer:
[C]
General Formulas and Concepts:
Chemistry
Kinetics
Equilibrium
Step-by-step explanation:
Equilibrium Expressions are only written for either aqueous solutions or gases. Solids and liquids are negligible for equilibrium. Our equilibrium constant expression would be 
![\displaystyle K = ([CO][H])/([H_2O])](https://img.qammunity.org/2022/formulas/chemistry/high-school/impprpxbkn5mq202t5z4vz3n1s91vfoal6.png) .
.
∴ Carbon C (s) is not included in the expression and is our answer.