Client.cs

public class Client
{
    public Client(string firstName, string lastName, string email, string password)
    {
        this.FirstName = firstName;
        this.LastName = lastName;
        this.Email = email;
        this.Password = password;
    }

    public Client()
    {
        this.FirstName = "Default First Name";
        this.LastName = "Default Last Name";
        this.Email = "myDefaultClientEmail@gmail.com";
        this.Password = "12345";
    }

    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
    public string Password { get; set; }
}