Consider the two 2-D cells given here. Which of these is correct? (Hint: Each face of an element points outside).

• A. S1i,j-1=S2i,j
• B. S1i,j-1=-S2i,j
• C. S3i,j-1=-S4i,j
• D. S3i,j-1=S4i,j
• E. .a) S1i,j-1=S2i,jb) S1i,j-1=-S2i,jc) S3i,j-1=-S4i,jd) S3i,j-1=S4i,j