Which of the following are the reasons/factors for exposure to benzene pollution? 1. Automobile exhaust 2. Tobacco smoke 3. Wood burning 4. Using varnished wooden furniture 5. Using products made of polyurethane Select the correct answer using the code given below:

Benzene is a volatile organic compound (VOC) and a known carcinogen. Exposure to benzene can occur from a wide variety of sources, both outdoor and indoor. Let's analyze each option: 1. **Automobile exhaust:** Correct. Benzene is a component of gasoline, and incomplete combustion in vehicle engines releases benzene into the atmosphere through exhaust fumes. 2. **Tobacco smoke:** Correct. Tobacco smoke, both active and passive (secondhand smoke), is a significant source of benzene exposure. Benzene is naturally present in tobacco leaves and is formed during the burning process. 3. **Wood burning:** Correct. The combustion of wood, whether in fireplaces, wood stoves, or through forest fires, releases various VOCs, including benzene, into the air. 4. **Using varnished wooden furniture:** Correct. Many varnishes, paints, glues, and coatings used on furniture contain solvents that can off-gas VOCs, including benzene, especially when the furniture is new or recently treated. This contributes to indoor air pollution. 5. **Using products made of polyurethane:** Correct. Polyurethane products, such as foams, adhesives, sealants, and coatings, can release benzene and other VOCs during their manufacturing process, application, and even as they age or degrade. This is particularly true for products that use benzene-containing solvents or precursors in their production. Therefore, all the listed activities/sources can contribute to human exposure to benzene pollution.