It is D, because looking at a unit circle, 5pi/3 is about the same location as -sqrt3 which is approximately 1.4.
Table 2 heheheheheehehehehheheheheehheheheheheheheehehehehhehehehehhehehehehehe
(6x6)x(6x6x6)=
(6x6x6x6x6)
((3x3x3)x(3x3x3)x(3x3x3)x(3x3x3))
try it on the calculator.
To subtract vectors, you simply have to subtract correspondent coordinates.
So, if you have

the subtraction is simply

So, in your case, we have
