Answer: the contents of a new textbook
Explanation:
The topic that is best suited for a formal discussion is the contents of a new textbook. This is suited to the formal discussion as it relates to educational settings such as a school.
Other options such as the weekend plans of your friends, the best places to shop online for new shoes and the best cookbooks for learning to make Thai food are all informal.
An observation?
an analysis?
i hope these help
The variant C. last week. It's not a verb at all.