Exp) Option d is the correct answer.

Statement 1 is incorrect: Naturally occurring nanoparticles can be found in volcanic ash, ocean spray, fine sand and dust, and even biological matter (e.g. viruses). Synthetic nanoparticles are equally, if not more diverse than their naturally occurring counterparts.

Statement 2 is correct: The field of nanotechnology is being greatly explored by cosmetic industries in order to improve the efficacy of cosmetic products. The cosmetics are formulated by using different types of metal and metal oxide nanoparticles such as silver nanoparticles (AgNPs), gold nanoparticles (AuNPs) and titanium dioxide nanoparticles (TiO2 NPs), zinc oxide nanoparticles, (ZnO NPs), iron oxide nanoparticles, (Fe2O3 NPs) and carbon-based NPs. The applications of different metal oxides as one of the active ingredients in cosmetics and sunscreens have attracted enormous interest from cosmetologists with advanced knowledge of chemistry, toxicology, dermatology, rheology, and even marketing.

Statement 3 is correct: According to the National Nanotechnology Initiative thousands of tons of silica, alumina and ceria, in the form of ultrafine abrasive particle mixtures including nanoparticles, are used each year in slurries for precision polishing of silicon wafers. The exposed population to nano materials continues to increase as their application expands. Despite obvious benefits of the power of small materials, there are open questions about how the nanoparticles used for day-to-day life may affect the environment. One of the crucial issues that have to be addressed in the near future, before massive fabrication of nano materials, is their toxicity to humans and impact on the environment.

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2844666/

https://sustainable-nano.com/2013/03/25/nanoparticles-are-all-around-us/