Step 1 :Calculate length of side AB: \(AB=(-1-4)^2+(-3-(-3))^2=|-5|^2+0^2=25\)
Step 2 :Calculate perimeter: \(2(L+W)=18\)
Step 3 :Since \(W+L=9\), check each coordinate and calculate L and W
Step 4 :Find \(a:(-1,6)\) and \(c:(4,6)\). Their difference matches the remaining L=W=4 \rightarrow Answer:a