You are deploying a mobile application for an eCommerce company. They require you to change themes based on the device type. Android devices see a green theme and iOS devices see blue. You are advised to use AWS Lambda for your mobile backend deployment. How could this be achieved efficiently?

Answer options:

A.Use a REST client to pass device info to API Gateway that invokes AWS Lambda function.
B.Different environment variables for Android and iOS.
C.Use AWS Mobile SDK and use the “context” object.
D.Use the “event” object to determine which device invoked the function.

Answer: C
Option A is incorrect as this is not very efficient as it requires writing code at the application level to send data to the Lambda function to process. 
Option B is incorrect as environment variables are used for more constant information and can be used during runtime.
Option C is CORRECT as per AWS Lambda FAQ’s the context object, when called through AWS Mobile SDK, will give the Lambda function automatic access to device and application information to them use to change themes.
 Option D is incorrect as the event object will not have the device information required.
Reference:
https://aws.amazon.com/lambda/faqs/