Answer:
D. 14
Explanation:
These triangles are something called a scale factor. A scale factor means when you multiply any side by that factor, you get the side of the other triangle. It is an exact copy of the triangle from before, just bigger or smaller, also known as set to scale. Here we can do 7/6 to find the scale factor (which is 1.16666666667), and multiply that factor by 12 to get 14.