Answer:
About 53.13 degrees.
Explanation:
If we draw the path of the hiker, or rather, all three vectors with vector B having its starting point at the end point of vector A, a right triangle is formed. We will most likely be using trigonometric functions to solve this.
vector A is parallel to the x axis (West - East), and vector B is perpendicular, so we'll be using the inverse tangent function to get the angle based on the ratio of the lengths of vector B to vector A, which is

atan
degrees.
If one would be pedantic, they'd say that the direction we have to go to get from vector C to vector A is clockwise, which is anti-mathematical, the true answer would be -53.13 degrees. Alternatively, whatever 360-53.13 is.