B

using System;

class SavingAccount{
    public static double annualInterestRate;
    private double savingsBalance;
    public double SavingsBalance{
        get {return savingsBalance;}
        set {savingsBalance = value;}
    }
    public void calculateMonthlyInterest(){
        double x = (savingsBalance * annualInterestRate * 1.0) / 12;
        savingsBalance += x;
    }
    public void modifyInterestRate(int newValue){
        annualInterestRate = newValue;
    }
}

class Program{
    public static void Main(){
        SavingAccount saver1 = new SavingAccount();
        SavingAccount saver2 = new SavingAccount();
        saver1.SavingsBalance = 2000.00;
        saver2.SavingsBalance = 3000.00;

        saver1.modifyInterestRate(3);
        saver1.calculateMonthlyInterest();
        saver2.calculateMonthlyInterest();
        Console.Write($"Saver1 - {saver1.SavingsBalance}, ");
        Console.Write($"Saver2 - {saver2.SavingsBalance}\n");

        saver1.modifyInterestRate(4);
        saver1.calculateMonthlyInterest();
        saver2.calculateMonthlyInterest();
        Console.WriteLine($"Next month: Saver1 - {saver1.SavingsBalance}, Saver2 - {saver2.SavingsBalance}");
    }
}