Which of the following tubes is not allowed as the stated frame member (regardless of implementation/mounting/etc.)?

1. 35mm x 1.2mm magnesium square tube as front bulkhead support (E=44 GPa)
2. 32mm x 2.5mm round aluminium tube as front roll hoop bracing (E=70 GPa)
3. 25.4mm x 2.4mm seam welded round steel tube as main hoop
4. 1" x 0.083" seamless drawn round steel tube as shoulder harness mounting barCorrect