Read the following passage:

Proudly he sent it off to Theo, saying “The Japanese draw quickly, very quickly like a lightning flash...I have only been here a few months, but tell me this-could I, in Paris, have done the drawing of the boats in an hour?” Instead of using a tool to draw in perspective, he wrote, “this is done without measuring, just by letting my pen go”.
What does perspective mean in this context?

viewpoint
the ruler
freehand
a technical term used in art