Which are the recommended best practices for using Oauth flows in this scenario?

Universal containers(UC) wants to integrate a third-party reward calculation system with salesforce to calculate rewards. Rewards will be calculated on a schedule basis and update back into salesforce. The integration between Salesforce and the reward calculation system needs to be secure.

Which are the recommended best practices for using Oauth flows in this scenario? Choose 2 answers
A . Oauth refresh token flow
B. Oauth SAML bearer assertion flow
C. Oauthjwt bearer token flow
D. Oauth Username-password flow

Answer: B,C