Answer:
The nonfiction texts which will most likely have a formal tone is:
a geography textbook
Step-by-step explanation:
The language used in a travel guidebook, a biography, and a blog post has an informal tone. These are the texts which are meant for the recreational and informative purpose. They not just give information about things and experiences but also informally treat their reader. On the other hand, a geography textbook will have the information written in a formal way to educate the reader.