I'm not sure of this one so I don't want to give you a wrong answer, but I'll cut it down to the last two options which I think are right. D and E. Take it from there.
Answer:
marble racing
Explanation:
it talks mostly about marble racing in this context but at the start it has Jelle Bakker and if it mentioned them more it would be about them
Answer:
They introduce a problem that 3-D printers could help solve.
Explanation:
I got right
