You are administering a continuous integration application that polls version control for changes and then launches new Amazon EC2 instances for a full suite of build tests. What should you do to ensure the lowest overall cost while being able to run as many tests in parallel as possible?

Answer options:

A.Perform syntax checking on the continuous integration system before launching a new Amazon EC2 instance for build test, unit and integration tests.
B.Perform syntax and build tests on the continuous integration system before launching the new Amazon EC2 instance unit and integration tests.
C.Perform all tests on the continuous integration system, using AWS OpsWorks for unit, integration, and build tests.
D.Perform syntax checking on the continuous integration system before launching a new AWS Data Pipeline for coordinating the output of unit, integration, and build tests.

Answer – B
Continuous Integration (CI) is a development practice that requires developers to integrate code into a shared repository several times a day. Each check-in is then verified by an automated build, allowing teams to detect problems early. 
Option A and D are invalid because you can build tests on a CI system and not only Syntax tests. And Syntax tests are normally done during coding time and not during the build time.
Option C is invalid because Opswork is ideally not used for build and integration tests.
For an example of a Continous integration system, please refer to the Jenkins system via the URL below
https://jenkins.io/