What is a runway incursion and what procedures minimize its risk?

What is a runway incursion and what procedures minimize its risk?

• A. Unauthorized presence of aircraft or vehicle on a runway; minimized by clearances, runway status awareness, ATC separation, and improved signage and lighting.
• B. An in-flight collision with another airplane in the air; minimized by TCAS.
• C. A misalignment of runway lights causing pilots to land on the wrong runway; minimized by pilot coordination.
• D. A weather event causing runway contamination; minimized by weather radar.

Answer: (A)