Oil burners can be divided into three classes:
1. air and steam atomizing burners
2. mechanical or pressure atomizing burners
3. centrifugal or rotary cup burners
4. atmospherical pressure burners
5. gravitational pressure burners
a) 1, 2, and 3
b) 1, 2, and 4
c) 2, 3, and 4
d) 3, 4, and 5
e) 2, 3, and 5
Answer: A