12. As shown in Figure 2, point $A$

is on the diagonal
of the parallelogram. Determine the relationship between $S_{1}$ and $S_{2}$ ( ).
(A) $S_{1}=S_{2}$
(B) $S_{1}>S_{2}$
(C) $S_{1}<S_{2}$
(D) Cannot be determined
12. A