Which one of these may have both class and individual characteristics?, Singapore

Question 1.12

Which one of these may have both class and individual characteristics?

1. Numerous small glass fragments recovered from the suspect’s clothing.
2. Paint smears found on the damaged fender of a car.
3. Partial bloody footprints found at the crime scene.
4. Soil patches embedded on the shoe sole.
5. Milk adulterated with urine.