Final answer:
The requirement for a reader to differentiate between two or more things is to consider how the things are different. Option c is the correct answer.
Step-by-step explanation:
The correct statement that defines the requirement for a reader to differentiate between two or more things is:
c) The reader must consider how the things are different.
To differentiate between two or more things, the reader needs to carefully consider the ways in which the things are different. This involves analyzing and comparing the characteristics, qualities, or aspects of the things to understand their distinctions. By doing so, the reader can gain a clearer understanding of the differences between the things being compared.