Dashboard for new users

I would like to ask what is the best solution for onboarding users dashboard.

Scenario A

1. when user login i will show them a big image to tell them that must add subscribers.
2. when they add 2 subscribers show the sidebar column with the list with subscribers.
3. and replace the image with the next task.

Scenario B

when user login i will show them a big image to tell them that must add subscribers and lock the sidebar widgets (ex. list of subscribers)

Scenario C

when user login i will show a popup for the next task.

Scenario D

Show all my dashboard and at the top of sidebar a small box with next task

Task:

1. Add new subscribers
2. Add new event
3. Send new sms campaign.
4. Send new email campaign.

The application is for event scheduler, email and sms newsletters