1(10p). True of False: a. The cross product of two unit vectors is always a unit vector. T F b. The curve r() = (2-V1-72 ,3v/1-12, v1-/2 +5) is a line segment. T F c. The function f(x, y) = etty cos(1 - x) sin(1 + y) has an absolute T F max and min on the closed disc of radius 2, centered at (1, -1). d. For any function continuous on the xy-plane, T F L f(x, Ddude =['S" f(x, y)dady. e. OF . dr =0 for any closed curve C. T F