Which of these taxpayers participates in a passive activity?

A. Brent. He owns and operates a car rental business.

B. Cheryl. She is a limited partner in a filmmaking partnership.

C. Joaquin. He is a real estate professional who materially participates in his business of renting and selling real property.

D. Margaret. As a securities trader, she is in the business of continually buying and selling securities for her own account and attempting to profit from short-term price swings.