Generative writing:
a. usually comes last in the writing process.
b. usually occurs during revision and editing in the writing process.
c. usually comes first in the writing process.
d. is not necessary part of the writing process.

Generative writing usually comes first in the writing process. 
It is the process of producing different ideas for the piece of literary work, for example, an essay or a short story. It is not the draft of the work. It is considered to be the process of generating the material that the author will be able to use in the drafting process. Authors can produce many short pieces that explore different ideas. It is an explorative process. The author is generating different ideas.