Correct Answer  Option 1 : position of negative charge alone
Ans: Option: 1
CONCEPT:

Coulomb's law: This law states that the electrostatic force of attraction between two charges is directly proportional to the product of their magnitude and inversely proportional to the square of the distance between them.
\(F= K\frac{Q_1 Q_2}{r^{2}}\)
Where F = Force of attraction, r = distance between two charges \(Q_1 \) and \(Q_2\) are two charges.
EXPLANATION:
According to coulomb's law \(F= K\frac{Q_1 Q_2}{r^{2}}\)
In question it is mentioned that a negative charge is placed at some point on the line joining the two charges, therefore the force is given as
\(F_1= K\frac{Q_1(q)}{r_{1}^{2}}\)
\(F_2 = K\frac{Q_2(q)}{r_{2}^{2}}\)
 The above equation shows that the direction of motion of the negative charge will depend upon the position of the negative charge alone.
So the correct option is 1.