According to "The NIST Definition of Cloud Computing," in PaaS, "the capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages, libraries, services, and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly configuration settings for the application-hosting environment.

Explanation
A retina scan could be used in conjunction with an RSA token because it is a biometric factor, and thus a different type of factor. An access card, RFID, and USB thumb drive are all items in possession of a user, the same as an RSA token, and as such would not be appropriate.

Modifying the metadata does not change the actual data. Although this initial phase is called
"create," it can also refer to modification. In essence, any time data is considered "new," it is in the create phase. This can come from data that is newly created, data that is imported into a system and is new to that system, or data that is already present and is modified into a new form or value.

Explanation
Integrity refers to the trustworthiness of data and whether its format and values are true and have not been corrupted or otherwise altered through unauthorized means. Confidentiality refers to keeping data from being access or viewed by unauthorized parties. Accessibility means that data is available and ready when needed by a user or service. Validity can mean a variety of things that are somewhat similar to integrity, but it's not the most appropriate answer in this case.

Data loss prevention (DLP) solutions allow for control of data outside of the application or original system. They can enforce granular control such as printing, copying, and being read by others, as well as forcing expiration of access. Intrusion detection system (IDS) and intrusion prevention system (IPS) solutions are used for detecting and blocking suspicious and malicious traffic, respectively, whereas a web application firewall (WAF) is used for enforcing security or other controls on web-based applications.