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? Choose2 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