A cylinderical pressure vessel of volume 6 m3 has to be designed to withstand a maximum internal pressure of 10 atm. The allowable design stress of the material is 125N/mm2 and corrosion allowance is 2 mm. The thickness of the vessel for a length/diameter ratio of 3 will be close to

• A. 5 mm
• B. 6 mm
• C. 8 mm
• D. 10 mm