This question is asking us to identify the answer choice that describes a principle that Gray uses in her work.
Answer choice B states that interior features can be essential in determining the overall structure. Lines 43-47 directly support this answer choice.
These lines state interior elements and structural elements are designed as an integrated whole. It also states that she applies her experience from lacquer to architecture, such that "it could only be achieved from the inside out".
I hope this helps. Please let me know if you have any other questions.