For the main hoop design, we would like to use the following steel (S275 with 0,25%C and 1,60%Mn). Which of the following sizes is according with the FS rules requirements?

1. Diam(ext)=30mm/Diam(int)=28mm
2. All the answers are wrong, because the steel does not meet with the minimum material specifications
3. Diam(ext)=28mm/Diam(int)=24mm
4. Diam(ext)=30mm/Diam(int)=26mmCorrect