Final answer:
The magnitude and direction of the electric field at point A can be determined by considering the vector sum of the charges. The electric field is a vector quantity, so it has both magnitude and direction.
Step-by-step explanation:
The magnitude and direction of the electric field at point A can be determined by considering the vector sum of the charges. The electric field is a vector quantity and has both magnitude and direction. The magnitude of the electric field is proportional to the net electric charge of the objects creating that field. Therefore, option A is the correct answer.