Answer: C) Alternate interior angles
The blue angles marked are inside the parallel lines, so they are considered interior. They are on alternating sides of the transversal line. The angles are only congruent when the lines are parallel.
The next number would be 19.
Each number adds one more each time.
For example, 4+0=4, 4+1=5, 5+2=7, 7+3=10, 10+4=14, 14+5=19
Hopefully this makes sense, its kind of hard to explain.
Hope this helps :)
The dimensions can vary. Here is a picture of a triangular prism with a right-triangle base.