How can a third-party application use Pega Platform?

To reduce training requirements for users, a company wants to utilize the existing front end of their application.

How can a third-party application use Pega Platform?
A . By using REST calls from the Pega API
B . By using database tables for staging the requests
C . By exposing third-party application services
D . By using middleware tools in application servers

Answer: A

Explanation:

Reference: https://www.pega.com/system/files/resources/2019-04/open-source-a-hybrid-approach-v2.pdf