A developer has created an AWS Lambda function in a company's development account.

To allow cross-account access to a KMS key, the key policy of the KMS key must grant permission to the external account or principal, and the IAM policy of the external account or principal must delegate the key policy permission. In this case, the new Lambda function in the development account needs to use the KMS key in the security account, so the key policy of the KMS key must allow access to the IAM role of the new Lambda function in the development account (option E), and the IAM role of the new Lambda function in the development account must have an IAM policy that allows access to the KMS key in the security account (option C). Option A is incorrect because it creates an IAM role for the new Lambda function in the security account, not in the development account. Option B is incorrect because it attaches a key policy to an IAM role, which is not valid. Option D is incorrect because it allows access to the IAM role of the new Lambda function in the security account, not in the development account.Verified References:

https://docs.aws.amazon.com/kms/latest/developerguide/key-policy-modifying-external-accounts.html

https://docs.aws.amazon.com/autoscaling/ec2/userguide/key-policy-requirements-EBS-encryption.html