The author develops this text structure by—

Answer choices for the above question

A. using the word but to identify differences.

B. discussing change over time to describe a solution to a problem.

C. starting many of the clauses with similar phrases to describe or define the qualities of two groups.

D. describing two groups’ feelings after the Challenger disaster to develop its effect.

Without any specific information about the text in question, it is impossible to determine the correct answer to the given question. Can you provide more context or details from the text?