Pegs are put in a board 1 unit apart both horizontally and vertically. A reubber band is stretched over 4 pegs as shown in the figure, forming a quadrilateral. Its area in square units is[asy]
int i,j;
for(i=0; i<5; i=i+1) {
for(j=0; j<4; j=j+1) {
dot((i,j));
}}
draw((0,1)--(1,3)--(4,1)--(3,0)--cycle, linewidth(0.7));
[/asy]<spanclass=′latex−bold′>(A)</span>4<spanclass=′latex−bold′>(B)</span>4.5<spanclass=′latex−bold′>(C)</span>5<spanclass=′latex−bold′>(D)</span>5.5<spanclass=′latex−bold′>(E)</span>6