outline.cs

    public class Product
    {
        public string Name { get; set; }
        public decimal Price { get; set; }
    }

    public class Trolley
    {
        public List<Product> Products { get; set; }
        public decimal Total { get; set; }
    }

    public class TrolleyCalculator
    {
        public Trolley CalculateTrolleyTotal(List<Product> products, List<SpecialOffer> specialOffers)
        {
            // TODO: Implement me
        }
    }

    public class SpecialOffer
    {
        public string Name { get; set; }
        public int Quantity { get; set; }
        public decimal Price { get; set; }
    }