Consider the following stencil.Assume that the grid is a uniform Cartesian grid. What is φw as given by the central difference scheme?(Note: Φ represents the flow variable).

• A. Φc
• B. \(\frac{\phi_c+\phi_w}{2}\)
• C. \(\frac{\phi_c-\phi_w}{2}\)
• D. \(\frac{\phi_w-\phi_c}{2}\)
• E. .a) Φcb) \(\frac{\phi_c+\phi_w}{2}\) c) \(\frac{\phi_c-\phi_w}{2}\) d) \(\frac{\phi_w-\phi_c}{2}\)