Who would most likely be upset that the author recommends the movie rather than the book?

Probably book lovers or people who prefer books over movies. Or if the reader really likes the author and the book VERY MUCH.

Hope this helps! :)

The one party who is most likely to be upset by the recommendation of the author is the book publisher.

In this particular era, people often prefer to watch the movie rather than read the book. Therefore, if even the author says that it is the movie they recommend, the majority of people will listen to their advice.

abruptly