How to fix score problems in C#

[HttpPost]
        public IActionResult SubmitTest(TestViewModel model)
        {
            // Check if the user has already passed the test
            bool hasPassed = HttpContext.Session.GetBool("TestPassed");

            // If the user has already passed, redirect to the course page
            if (hasPassed)
            {
                return RedirectToAction("TakeCourse", "Courses");
            }

            // Retrieve the module and questions from the database
            Module module = _context.Modules.FirstOrDefault(m => m.ID == model.ModuleID);
            List<Question> questions = GetQuestionsForModule(module);

            // Keep track of the user's score
            int score = 0;

            // Iterate over the questions and check the selected answers
            for (int i = 0; i < questions.Count; i++)
            {
                Question question = questions[i];

                // Get the selected answer(s) for the current question
                int[] selectedAnswerIds = model.Answers
                    .Where(a => a.QuestionID == question.Id)
                    .Select(a => a.ID)
                    .ToArray();

                // Get the answer count for the current question
                int answerCount = GetAnswerCountForQuestion(question.Id);

                // Check if the question is a radio type
                if (question.QuestionType == QuestionType.RADIO)
                {
                    // Retrieve the correct answer for the question
                    Answer correctAnswer = question.Answers.FirstOrDefault(a => a.IsCorrectAnswer);

                    // Check if the selected answer matches the correct answer
                    if (correctAnswer != null && selectedAnswerIds.Length == 1 && correctAnswer.IsCorrectAnswer)
                    {
                        // Increase the score if the selected answer is correct
                        score++;
                    }
                }
                // Check if the question is a checkbox type
                else if (question.QuestionType == QuestionType.CHECKBOX)
                {
                    // Retrieve the correct answers for the question
                    List<Answer> correctAnswers = question.Answers.Where(a => a.IsCorrectAnswer).ToList();

                    // Check if all selected answers are correct and no incorrect answers are selected
                    if (correctAnswers.Count == selectedAnswerIds.Length &&
                        selectedAnswerIds.All(id => correctAnswers.Any(a => a.ID == id && a.IsCorrectAnswer)))
                    {
                        // Increase the score if all selected answers are correct
                        score++;
                    }
                }
            }

            
            
            // Determine if the user passed or failed the test based on the score
            bool passed = score == questions.Count;

            // If the user passed, store the information in the session and redirect to the course page
            if (passed)
            {
                HttpContext.Session.SetBool("TestPassed", true);
                return RedirectToAction("TakeCourse", "Courses");
            }
            else
            {
                // Redirect back to the test page with a failure message
                TempData["TestResult"] = "You failed the test.";
                return RedirectToAction("TakeTest", new { moduleId = model.ModuleID });
            }
        }