Step 1: Understand the centroid property.
The centroid \( G \) of a triangle divides each median in the ratio 2:1. The position vector of the centroid is the average of the position vectors of the vertices. The sum of the position vectors of any point and the centroid is 4 times the vector from the centroid to the point.
Step 2: Conclusion.
Thus, the sum \( OA + OB + OC + OG = 4OG \), corresponding to option (A).