<human>: Which of the following solutions is better for the following goal:
To tell a real diamond from a fake.

OPTIONS:
- Try using fog - try to fog it up with a fog machine. Glass will stay fogged much longer than diamond.
- Try using fog - try to fog it up with your mouth like a mirror. Glass will stay fogged much longer than diamond.
<bot>: Try using fog - try to fog it up with your mouth like a mirror. Glass will stay fogged much longer than diamond.