Final answer:
The correct starting point for cutting a triangular long layered haircut is at the nape of the neck.
Step-by-step explanation:
The correct answer is a) At the nape of the neck. When cutting a triangular long layered haircut, you typically begin at the nape of the neck, which is the hairline at the back of the neck. This is because the shape of the haircut starts with a central point at the nape and gradually builds layers towards the top. Starting at the nape allows for a balanced and even distribution of layers throughout the hair.