A \[\frac{1}{2}(1 + sen \theta) u^{2}\] B \[( 1 + sen \theta) u^{2}\] C \[\frac{3}{4} (1 - sen \theta) u^{2}\] D \[\frac{1}{2}(1 + cos \theta ) u^{2}\] E \[\frac{1}{2} ( 1 + 2 sen\theta ) u^{2}\]