The table for continuous functions W(x) and Z(x) lists the sign of W(x)-Z(x) across [-7,7]: W(x)>Z(x) on (-7,-6); Z(x)>W(x) on (-6,-4); W(x)>Z(x) on (-4,-1); Z(x)>W(x) on (-1,2); W(x)>Z(x) on (2,6); Z(x)>W(x) on (6,7). The zeros are x=-6, -4, -1, 2, and 6. Which expression gives the total area between the curves?