Best card choice in card game in C#

Question

The problem consists in choosing the best option at every moment of the game following these rules:

• You can only pick the leftmost or the rightmost card.

Answer 1

This is the code that actually worked in the end. Thanks to everyone for your support.

    static int cardGameValue(List D, int myScore, int opponentScore)
    {
        if (D.Count == 0) return myScore;
        else if (D.Count == 1)
        {
            opponentScore += D[0];
            return myScore;
        }
        else
        {
            if (D[0] <= D[D.Count - 1])
            {
                opponentScore += D[D.Count - 1];
                D.RemoveAt(D.Count - 1);
            }
            else
            {
                opponentScore += D[0];
                D.RemoveAt(0);
            }

            int left = cardGameValue(new List(D.GetRange(1, D.Count - 1)), myScore + D[0], opponentScore);

            int right = cardGameValue(new List(D.GetRange(0, D.Count - 1)), myScore + D[D.Count - 1], opponentScore);

            if (left >= right)
            {
                return left;
            }
            else
            {
                return right;
            }
        }
    }