Why are There 3 Prompt Choices For Each Inspiration?

As an example, one set of inspirations is photos – unusual and interesting photos.  I have over 30 of them. Each photograph comes with three prompts from which students choose to write on one.
Why 3 choices?  Several reasons:

•  Having Choices matters. Testosterone, specifically, is part of the drive for independence.  Girls have testosterone, as well as boys, just less of it. So, choices matter for students’ feeling like they have control.
• To extend the writing.If a student runs out of things to say on one prompt, they can simply draw a line and continue on the next one. The point of the exercise is to build fluency.
• But, no more than 3 prompts, because too much time is then wasted deciding.