Answer:
A. Solid Line
Step-by-step explanation:
"A visible line, or object line is a thick continuous line, used to outline the visible edges or contours of an object. A hidden line, also known as a hidden object line is a medium weight line, made of short dashes about 1/8” long with 1/16”gaps, to show edges, surfaces and corners which cannot be seen (Open Oregon)."
It doesn't directly say that, but that's what I'm inferring from its context.
Okay, I hope this helps in some way! Have a wonderful day! :)