The first step in developing a thesis statement usually involves

a. identifying details gathered while prewriting and organizing them into groups of related ideas.
b. drafting an outline.
c. freewriting and brainstorming.
d. creating a graphic organizer that lists all of the evidence you plan to present.

A. identifying details gathered while prewriting and organizing them into groups of related ideas.  

Explanation:

A thesis statement identifies the topic that will be discussed in the paper, therefore it must be clear and it should only cover what is going to be discussed, it is also used to generate interest in your topic. It should be narrowed down to a specific topic and points towards a conclusion.  

Hence, in order to write it, you need to identify all the details that are actually related to your topic so you won't deviate from the subject,

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