Correct Answer - B.
AWS::Serverless::Application resource in AWS SAM template is used to embed application from Amazon S3 buckets.
Option A is incorrect as AWS::Serverless::API is used for creating API Gateway resources & methods that can be invoked through HTTPS endpoints.
Option C is incorrect as AWS::Serverless::LayerVersion resource type creates Lambda layered function.
Option D is incorrect as AWS::Serverless::Function resource describes the configuration for creating Lambda function.