Impressionist painters try to capture their outdoor settings quickly and

A. In a single sitting
B. At the same time of the day until they were finished
C. Precisely

as they appear in reality

The correct answer is A. In a single sitting. Impressionist painters aimed to capture the fleeting effects of light and atmosphere in their outdoor scenes, so they often painted en plein air (outdoors) and worked quickly to capture the essence of their surroundings in one sitting. This approach allowed them to portray the changing qualities of light and color in a spontaneous and immediate manner.