Answer:
Part B
This statement means that we are 95% confident that our confidence interval and our point estimate of our results from this sample contains the true proportion of national adults who fulfill a certain condition. The margin of error is plus or minus 4 percentage points in our survey, so we are fairly accurate / close to our point estimate.
Part C
Personally, I think that the minimum quota should be different, because nowadays very few people have landlines, and most people have cell phones. I would put it at 80% cell phones, 20% landlines, for the most representative survey possible.
Part D
Unfortunately, there isn't enough information to explain this one, because I can't see the link or view the responses and trends. I would give you the advice that you might want to include all variables and survey conditions: what type of survey was it? how many adults were sampled? what are your hypotheses or preconceived notions? what is the standard error? This should help; if not, please clarify.