Consider the following statements : 1. Other than those made by humans, nanoparticles do not exist in nature. 2. Nanoparticles of some metallic oxides are used in the manufacture of some cosmetics. 3. Nanoparticles of some commercial products which enter the environment are unsafe for humans. Which of the statements given above is/are correct ?

Option (d) is correct because metallic oxides like zinc oxide and titanium dioxide are standard ingredients in cosmetics like sunscreens (Statement 2), and many commercial nanoparticles are known to be toxic and unsafe due to their ability to bioaccumulate in the environment (Statement 3). Statement 1 is a common trap and is incorrect because nanoparticles occur naturally in volcanic ash, sea spray, and smoke, which makes options (a) and (c) wrong. The core concept being tested is the fundamental understanding of nanotechnology, specifically its diverse origins (natural vs. anthropogenic), practical applications, and environmental impact.