Answer: A) this author is qualified to write this article.
Step-by-step explanation: In the given scenario we are told that there is a pediatrician that wrote an article about childhood vaccinations, when we evaluate the author's qualifications to write this article, we need to include the educational background of the author and compare this background to the theme of the article to see if they match. In this case, the author is a pediatrician (a doctor specialized in treating children) and the article is about childhood vaccination, so we can say that the author is qualified to write this article.