Answer : The concentration of the NaOH solution is, 0.738 M
Explanation :
To calculate the concentration of base, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is NaOH.
We are given:

Putting values in above equation, we get:


Thus, the concentration of the NaOH solution is, 0.738 M
The correct option is A.
A chemical reaction is said to have reached an equilibrium stage if the rate of reaction of the forward reaction is equal to the rate of reaction of the reverse reaction. Two way arrows are usually used to depict equilibrium reactions. These arrows indicate that the chemical reaction can move both ways. At the equilibrium point the concentrations of both the reactants and the products are equal.