What is the artificial activity which indicates that an activity following it, cannot be started unless the preceding activity is complete known as?

Called integration in the industry can be vertical in this supplementary industriesBut if the project is in the same production line single or continuous output

Option " C "                            .

Thanks for invite , I think c : dummy

............option    c..........

Thanks for invitation 

•  

  B.     free float

   

This activity is known as : Free float

I choose : B 

its called ....    C.dummy  activity

Any artificial activity would be termed as 'Dummy' activity.

thanks for invition ,,,,,,,,,,

my choice is option C