using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        Dictionary<string, List<string>> test = new()

        {

            { "animal", ["cat", "dog"] },

            { "fruit", ["banana", "apple"] }

        };

        var result = test.SelectMany(x => x.Value.Select(y => (x.Key, y)))

            .ToList();

        foreach (var item in result)

            Console.WriteLine($"{item.Item1} {item.Item2}");

    }

}