Question from the C# - Fundamentals test

public Age { get { return this.age; } set {this.age = value;} }

public int Age { get { return this.age; } set {this.age = valeur;} }

public int Age { get { return this.age; } set {this.age = value;} }

public void Age { get { return this.age; } set {this.age = value;} }