The unit vector in the direction of the vector from P 1(1,0,1) to P2 (3,2,0) isAi+j+kB2i +2j-kC(2/3)i 1 (2/3)j - kD(2/3)i + (2/3)j - k/3Answer: D. (2/3)i + (2/3)j - k/3