The answer is indeed option A. web diagramming.
Web diagramming helps in the writing process by connecting objects and ideas, illustrating the big picture of a story, an argument etc. There is the main idea linked to other topics or details directly related to it. These other ideas may be further unfolded and connected to even more details.
Free writing is a technique that helps authors write in a raw way, not worrying about style or grammatical correction, for instance. It is a way to let ideas flow unblocked, free. Most of the material produced by this technique may not be used later, but it helps developing a thought.
I wasn't able to connect blueprinting to writing at all. It is usually related to engineering.
Looping is a continuation of free writing. The author may choose a sentence or a topic produced while free writing and develop that topic.
