Final answer:
The correct answer is G, as statements A-F are not necessarily true without more information. There must be a net force to the right for an object to accelerate to the right, yet forces could exist in other directions, balanced that do not influence the horizontal acceleration.
Step-by-step explanation:
If an object is observed to be moving to the right and speeding up, it is accelerating in the direction of motion. Answer A states that there is at least one force acting on this object that is directed to the right. This statement is true because for an object to accelerate to the right, according to Newton's second law, there must be a net force acting in that direction.
However, answer B, which suggests that there are no forces acting to the left, is not necessarily true; there could be forces acting to the left, but as long as the net force is to the right, the object will continue to accelerate to the right. Similarly, answers C and D, which suggest that there are no forces acting vertically, cannot be confirmed without additional information. Forces could act vertically -- either up or down -- but if these forces are balanced, they will not affect the horizontal acceleration.
Answer E is not correct because if there were no net force horizontally, the object would not accelerate. Answer F about no net force vertically could be true if the forces in the vertical direction are balanced. But it is not necessarily related to the object moving to the right and accelerating. Thus, G is the only correct choice as none of the choices A-F are completely true without additional context.