I am confused by this as well, but I do believe it has to do with 'Billboards are the basis of our business' is an actual statement within the original sentence and "that there is a definite relationship between X and Y" is a part of the original sentence and not a statement within it.

Can someone please explain this^^^

This is what I thought the answer was as well

Question one doesn't make sense to me; the conclusion is having blue eyes is related to genetics but neither of the two premises mentions genetics. I thought we weren't supposed to implied real life information to the questions unless it is given. So how can "This suggests that having blue eyes is largely determined by genetics." be the conclusion when this is the first mentioning of genetics? #feedback