When I saw the newsletter, which presents only the question but not the answer options, I was afraid that this would be a debatable question, since many design best practices are more or less subjective and far from carved in stone.
Luckily, that was not the case. The author picked best and worse practices that were so obvious that I would have expected a correct answer rate of at least 90%.
The current rate is 82%. Obviously, even this basic knowledge is in dire need of reinforcement for 18% of the users of this site. Which makes this a good and valuable question.
Hugo Kornelis, SQL Server/Data Platform MVP (2006-2016)
Visit my SQL Server blog: http://sqlblog.com/blogs/hugo_kornelis