Object Oriented Bank Account With Overrides

Bank.cs

// C# code​​​​​​‌‌‌​​​‌‌​‌​‌​‌‌​​​‌​‌‌‌​‌ below
using System;

// Write your answer here, and then test your code.
// Your job is to implement the findLargest() method.

public class Answer {

    // Change these Boolean values to control whether you see 
    // the expected result and/or hints.
   public  static Boolean ShowExpectedResult = false;
   public  static Boolean ShowHints = false;

}

public class BankAccount {
    private string _FirstName;
    private string _LastName;
    private decimal _Balance = 0.0m;

    public BankAccount(string firstName, string lastName, decimal balance = 0.0m) { 
        this._FirstName = firstName;
        this._LastName = lastName;
        this._Balance = balance;
    }

    public decimal Balance(){
        return this._Balance;
    }
    public void Balance(decimal b){
        this._Balance = b;
    }
    public string AccountOwner(){
        return $"{_FirstName} {_LastName}";
    }
    public void Deposit(decimal deposit){
        this._Balance += deposit;
    }
    public virtual void Withdraw(decimal withdraw) { }
}

public class CheckingAcct : BankAccount {
    public CheckingAcct(string firstName, string lastName, decimal balance)
    :base(firstName, lastName, balance){

    }

    public override void Withdraw(decimal withdraw){
        if (withdraw > Balance()){
            Balance(Balance() - (withdraw + 35));
        } else {
            Balance(Balance() - withdraw);
        }
    }
}

public class SavingsAcct : BankAccount {
    private decimal _InterestRate;
    private int _wdcount = 0;

    public SavingsAcct(string firstName, string lastName, decimal ir, decimal balance)
    :base(firstName, lastName, balance)
    {
        this._InterestRate = ir;
    }
    public decimal InterestRate(){
        return _InterestRate;
    }
    public void ApplyInterest(){
        Balance(Balance() + (Balance() * _InterestRate));
    }
    public override void Withdraw(decimal withdraw)
    {
        if (withdraw > Balance()){
            return;
        } else {
            if (_wdcount >= 3){
                Balance(Balance() - (withdraw + 2));
                return;
            }
            _wdcount++;
            Balance(Balance() - withdraw);
        }
    }
}