You got it. A survey is evidence. Always be wary when you see surveys. Also be wary when you see the word "opinion." Here, we didn't even have to get into what "dominant in the market" meant or even pay attention to the numbers 75% versus 50%. The premise relied on the "opinion" of people, and then assumed that the opinion was in fact true. So if you ever see that flaw, look for an answer choice like "taking evidence that a claim is believed to be true to constitute evidence that the claim is in fact true."
For the future/past question: Pay close attention to the conclusion - "Harrold Foods dominates the market now and need only maintain its current market share in order to continue to do so." It is not about advertising or whether Harrold Foods WILL dominate the market in the future. But only that it is dominant now and need only maintain its current market share (this author seems to believe it's 72%) to continue dominating (being above 50%). Seems like an obvious statement, but only if you believe the survey represents actual market share.