For a linear elastic structural system, minimization of potential energy yields

The plane frame below is analyzed by neglecting axial deformations. Following statements are made with respect to the analysis :

$$1.$$$$\,\,\,\,\,\,\,$$ Column $$AB$$ carries axial force only.
$$2.$$$$\,\,\,\,\,\,\,$$ Vertical deflection at the center of beam $$BC$$ is $$1mm.$$

Which of the following applies?

For the plane truss shown in the figure, the number of zero force members for the given loading is

For linear elastic frame, if stiffness matrix is doubled with respect to the existing stiffness matrix, the deflection of the resulting frame will be