Based on the context of this excerpt from w. w. jacobs's "the monkey's paw," what does the word placidly mean?

without, the night was cold and wet, but in the small parlour of laburnam villa the blinds were drawn and the fire burned brightly. father and son were at chess, the former, who possessed ideas about the game involving radical changes, putting his king into such sharp and unnecessary perils that it even provoked comment from the white-haired old lady knitting placidly by the fire. A completing a task in a frantic mannerB having a particular motive for an actionC appearing to be calm and relaxedD acting harshly or stubbornly

C. Appearing to be calm and relaxed.

Explanation:

The word "placid" literally means anything that appears to be calm and peaceful on the surface, with barely any or no movement.

The given excerpt from "The Monkey's Paw" by W.W. Jacobs gave a description of the White family before they encounter the monkey's paw. The image of the night before the 'curse' encountered them "was cold and wet" with the father-son duo playing a game of chess. On the side, near the fire was the mother observing the game. The very act of the father in putting his king at risk produced a sharp comment from the mother, who was calmly knitting. The word "placidly" in the given passage suggests that she appears to be calm and relaxed.