This question is incomplete because the options are missing; here is the complete question:
Which nonfiction genre instructs or teaches the reader how to do something?
A. How-to
B. History
C. Humor
D. Biography
The answer is A. How-to
Step-by-step explanation:
In general, texts are classified into genres according to their function and features. In the case of texts such as manuals or recipes that guide readers through a process or teach them something, these belong to the how-to genre. The how-to genre as indicated by its name focuses on "how to do" things for example, how to cook lasagna or how to repair the washing machine. Moreover, this is part of nonfiction writing because it is based on real processes. According to this, this is the genre that instructs readers on how to do something.