Option D, "Browse the App Exchange to look for a potential partner App which can be directly installed " would best satisfy the given requirement.
Explanation:
Lightning Platform (also called Force.com) is a network for the development of add-on services in a single application called Salesforce.
CRM Software Business solutions, The Sales force Cloud is a CURM suite providing solutions to small, medium-sized and enterprises with an emphasis on sales and support. The CLC provides customer relations.
The AppExchange provides mobile software and consulting tools as a robust platform. First has to be a Sales force member till you can render your own product or software publicly available to potential clients.