EXPLANATION
Writing the component form from the given magnitude and direction:
[tex]v=<\lvert{10}\rvert\cos240,\lvert{10}\rvert\sin240>[/tex]
Computing the arguments:
[tex]v=<10*(-\frac{1}{2}),10*(-\frac{\sqrt{3}}{2})>[/tex]
Multiplying numbers:
[tex]v=<-5,-5\sqrt{3}>[/tex]
In conclusion, the solution is the last option.
