When encountering a misstatement in sampling, the appropriate actions to take include: A. Determining the nature and causes of the misstatement is crucial to understand the underlying issue. B. Calculating the projected representative misstatement helps to assess the potential impact on the financial statements. C. Applying professional judgment to decide whether to revise the Tolerable Error (TE) is essential to ensure an effective audit.

Therefore, all of the options provided (A, B, and C) are relevant actions to take when a misstatement is encountered in sampling. So, the correct answer is: D. All of the above.