The project management phases are broken down into five phases$\_\_\_\_\_$First$,$ stakeholders initiate the project, and then define and plan it$.$ Next, the team executes the project and monitors its performance. Finally, once the project is completed, it must be closed out$($Eby$).$

Which of the following punctuation marks is missing from the above sentence?

Group of answer choices

period

semicolon

ellipsis

comma