What can one conclude about the displacement components ux and uy in the finite element model of the plane elasticity equations?

• A. They are primary variables and must be carried as primary nodal degrees of freedom
• B. They are secondary variables and must be carried as primary nodal degrees of freedom
• C. They are primary variables and must be carried as secondary nodal degrees of freedom
• D. They are secondary variables and must be carried as secondary nodal degrees of freedom