This depends on whether you treat the core as a single layer or split it into the outer and inner core.
The Earth's core has a radius of approximately 3,470 km whereas the Earth's crust is on average only 60 km thick.
This as a fraction is 60/3,470 which can be simplified to 1/58.
That means that the core is approximately 58 times thicker than the crust.
The mantle (which is thickest if you split the core into it's inner and outer components) is 2830 km thick.
This as a fraction is 60/2,830 which simplifies to approximately 1/47.
The silk road can promote the cluture communicating and the economic development by linking China and counties all over the world. For exampe, Chinese could go to India to learn the Buddhism and bring it back. And Chinese could also spread Chinese culture to other countries.
C is one but idk about the others, b might be one also
Greece's economy prospered thanks to trade. Hope this helps.
Take care,
Diana