Which one is the correct sequence of constructing a basement in top down construction?

Question

Accepted Answer

Build retaining wall --> Install prefounded columns --> Build ground floor slab --> Excavation --> Build basement slabs

Answer

Build retaining wall --> Excavation --> Build basement slabs --> Install prefounded columns --> Build ground floor slab

Answer

Excavation --> Build ground floor slab --> Build basement slabs --> Install prefounded columns --> Build retaining wall

Answer

Install prefounded columns --> Build ground floor slab --> Excavation --> Build basement slabs --> Build retaining wall

Answer

Excavation --> Build retaining wall --> Build ground floor slab --> Build basement slabs --> Install prefounded columns

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