Explanation:

- Turbulence generally refers to disorder or chaos. It’s often used to describe rough or erratic air movement or a state of confusion.

- Option 1: Calm - This word means a state of peace or tranquility. It's the absence of noise, violence, or similar disturbances. ?? This is the correct antonym for turbulence.

- Option 2: Causing disturbance - This is actually similar to turbulence. It refers to something that causes disruption or disorder.

- Option 3: Ignorance - This involves a lack of knowledge or awareness. It's unrelated to turbulence and doesn't make a fitting antonym.

- Option 4: Quickness - Speed or rapidity. While it can comment on fast movement, it's not specifically opposite to turbulence.

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