What percentage of NATS is owned by Heathrow Airport Holdings Ltd?

Answer: A — 4%

Heathrow Airport Holdings Ltd owns 5% of NATS. This ownership structure reflects a strategic investment in air traffic services that integrate with one of the UK's primary airports. This percentage is significant as it demonstrates the involvement of major airports in the governance and operational framework of air traffic services, allowing for better alignment of air traffic management with airport operations and capacity planning. The level of financial stake held by such entities often influences collaborations and joint ventures aimed at enhancing airport and airspace efficiency. Having a minor stake like 4% may suggest a lesser degree of influence and interest, which is not the case with Heathrow Airport Holdings Ltd, making the correct answer 5%.