It depends. If your (only) weak section is RC like me, then Flex is harder to score. I averaged at177+ on full-length test, but got mid-low170s on Flex because it’s shorter. Another LR section will give me “free points” to comfortably sit in the mid-high 170s. FLEX benefits test takers weak at LR/good at RC/tend to have good luck/most affected by fatigue/can only take paper test if not for FLEX. For those in the low170s on regular tests, they will get 175+ with a strong RC or good luck, of course. The net effect will be more high scorers proportionally, I think, because more people are better off.

Mario obviously agrees with B, but according to Renate, "all this means'' is a wide-open market. It's too much of a stretch to equate this to a good idea to open a rug store. Like Renate says, it only suggests the market is wide open. I think it's common sense that there are many factors other than the openness of the market that matter. And from "all this means", I don't sense that Renate means to extend her idea beyond an open market.

For C, Mario agrees it's possible to determine the market: "there's little demand for rugs". Renate again may or may not agree. She says the market is wide open now, but that doesn't mean it's possible to determine the market. No supply doesn't suggest anything on the demand. It only means you're going to capture the whole market. Whether it's possible to determine the market, Renate doesn't offer any clue.

B is the better choice because it's better supported. While you can't infer it's a good idea to open a rug store from Renate's words, what she says definitely strengthens that. So there's evidence supporting those two may disagree on B. With C, it's much less obvious. Renate's statements don't support that it's impossible to determine the market.