You’ve just started developing an application on your On-premise network. This application will interact with the Simple Storage Service and some DynamoDB tables. As the developer, how would you ensure that your SDK can interact with the AWS services on the cloud in the most secure manner?

Answer options:

A.Create an IAM Role with the required permissions and add it to your workstation.
B.Create an IAM Role with the required permissions and make a call to the STS service.
C.Create an IAM User, generate access keys, then use them from within your program.
D.Create an IAM User, generate a security token, and use the Security Token from within your program.

Answer – B
An IAM role can be created to ensure the SDK can interact with AWS services on the cloud. 
https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_temp_use-resources.html
Option A is incorrect because an on-premise workstation should not use IAM Roles. 
Option C is incorrect because IAM User should not be used in this scenario because the question is asking for the most secure option here.
Option D is incorrect since we should not generate a security token to interact with the various AWS services during the development phase.
For more information on the usage of credentials in AWS, please refer to the below link-
https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html