Final answer:
AWS allows for vulnerability and security assessments on specified resources, but with prior consent and approval. It is a shared responsibility, with AWS securing the cloud while customers secure their content. Third parties can be contracted to carry out assessments within AWS's guidelines.
Step-by-step explanation:
Regarding the vulnerability and security assessment on AWS resources, it's important to distinguish between AWS's responsibility and the customer's responsibility. AWS follows the 'shared responsibility model' for cloud security. This means AWS is responsible for the security 'of' the cloud, while customers are responsible for security 'in' the cloud. Option D is correct as AWS does allow customers to run vulnerability and penetration tests on their AWS instances, but this must be done with prior consent and approval from AWS to ensure compliance with the AWS Acceptable Use Policy. Options B and C are also true to some extent; organisations are permitted to contract third-party organisations for assessments, and they can conduct vulnerability and security assessments on specified AWS resources that are covered under their AWS agreement and after fulfilling AWS requirements for such tests. Option A is false because AWS clearly permits vulnerability and penetration testing on customer instances within certain guidelines.