Which is a non-contact force?

1. Contact forces act only when two bodies are in physical contact, such as friction and tension. 2. Gravitational force acts between two masses across empty space. 3. Therefore gravity is a non-contact force. 4. Friction, tension and normal reaction all require direct contact. _Source: Selina Concise Physics ICSE Class 9, Ch 3 'Laws of Motion' (aplustopper.com extract)_