Explanation
Shares are used within a cloud environment to prioritize resource allocation when customer requests exceed the available resources. Cloud providers utilize shares by assigning a priority score to each customer and allocating resources to those with the highest scores first. Scoring is a component of shares that determines the actual order in which to allocate resources. Neither weighting nor prioritization is the correct term in this case.

Explanation
Regardless of the particular cloud service used, physical security of hardware and facilities is always the sole responsibility of the cloud provider. The cloud provider may release information about their physical security policies and procedures to ensure any particular requirements of potential customers will meet their regulatory obligations. Personal security of developers and regulatory compliance are always the responsibility of the cloud customer. Responsibility for operating systems, and the auditing of them, will differ based on the cloud service category used.

Explanation
Data masking does not support authentication in any way. All the others are excellent use cases for data masking.