The writer was an authoritative source on the topic. She held many degrees, was a guest on talk shows, and wrote many books. Wha
t impressed me was that she actually lived the experiences that she wrote about. Which word has the closest meaning to authoritative as it is used in the first sentence?
It appears that the best word choice here is going to be <em>reliable</em>. Time and time again, the person who wrote this passage discusses how many times the writer has discussed this topic.
This shows that she is going to be <em>reliable</em>, because of her experience and intelligence. Also, it helps that <em>reliable </em>is in the official thesaurus for <em>authoritative.</em> Hopefully, I didn't mess up this time, Brook!