Answer:
D. Fourth, the invitations should be sent.
Step-by-step explanation:
The paragraph describes the different steps a person should follow to have a successful party. Different enumerators are used: first, second, third and finally. These clues reflect that a fourth step is needed. Besides, the last step is closely related to sendind the invitations to the guests. If they guests do not learn about the party, there will not be one.