1. **Problem:** How many triangles can you identify in the given figure where a square is divided by its diagonals into four triangles, then further divided by a vertical line through the center creating 8 smaller triangles in total? 2. **Understanding the figure:** The square is first divided by its two diagonals, creating 4 triangles. 3. Then, a vertical line through the center divides each of these 4 triangles into 2 smaller triangles, doubling the count to 8. 4. **Counting triangles:** Each of these 8 smaller triangles is distinct. 5. Therefore, the total number of triangles in the figure is $8$. 6. **Answer:** The correct choice is d) 8.