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 :

1. (a)1, 2 and 3 only
2. (b)2 and 4 only
3. (c)1, 3 and 4 only
4. (d)1, 2, 3, 4 and 5