I keep getting error CS0165

The exercise is The-Object-of-Your-Affection. When I try to loop through the array hobbies to format it the way I want I get the error CS0165: Use of unassigned local variable ‘hobby’. Here is the code I have so far:

Program.cs

using System; namespace DatingProfile { class Program { static void Main(string[] args) { Profile sam = new Profile(name: "Sam Drakkila", age: 30, city: "New York", country: "USA", pronouns: "he/him"); string[] h = {"stuff", "things", "whatnot"}; sam.SetHobbies(h); Console.WriteLine(sam.ViewProfile()); } } }

Profile.cs
The error is in this file. The method starts on line 29.

using System; namespace DatingProfile { class Profile{ // Fields private string name; private int age; private string city; private string country; private string pronouns; private string[] hobbies; // Constructors public Profile(string name, int age, string city, string country, string pronouns = "they/them") { this.name = name; this.age = age; this.city = city; this.country = country; this.pronouns = pronouns; this.hobbies = new string[0]; } // public methods public string ViewProfile(){ string hobby; foreach (string i in this.hobbies){ hobby += $"o {i}\n"; } string info = $"{this.name} is {this.age} and lives in {this.city}, {this.country}. {this.name}'s pronouns are {this.pronouns}.\nThere hobbies are:\n{hobby}"; return info; } public void SetHobbies(string[] hobbies){ this.hobbies = hobbies; } } }