What is the prerequisite for a costumer to enable Docusign as their signature tool?

What is the prerequisite for a costumer to enable Docusign as their signature tool?
A . The docusign application is enabled on the costumers mobile devices
B. The costumers existing docusign account can be used for onboarding only
C. An embedded signature is enabled
D. The costumer needs a docusign account

Answer: D