Answer:
The last choice is your answer
Step-by-step explanation:
Plot your point in an x/y coordinate plane.  We are in QII where x is negative and y is positive.  From that point, if you drop an altitude to the negative x axis, you have a right triangle with a base measure of -2, a height of 5 and a hypotenuse that is unknown as of right now.  We will find it using Pythagorean's Theorem.  
The length of the hypotenuse is √29.  That means that the cosine of that angle is the side adjacent over the hypotenuse.  Rationalizing the denominator gives us 