Part C of the board exam is the clinical part. 250 questions, after watching a video, reading a vignette or listening to an audio clip.
The problem is, this part is new and the review courses are still learning about it. I found this part to the hardest, and also scored the lowest on. At the time, I thought I had gotten most of the questions wrong.
Did you do Beat the Boards? Their videos are fairly good. But knowing their notes cold will help the most on the clinical part also. The content questions are doable on part C. But the problem with this section is that you have to think in a broad sense. They will present some vague vignette, and ask you to select all possible diagnosis. And if you miss one, you get the question wrong. I would recommend multiple reviews of the BTB notes for this section.
When looking at the video example the ABPN has on their website, I tried to think of other possible scenarios, the types of questions they asked and how it was all worded.