Which of following are valid severity levels for host updates in vCenter Update Manger (Choose Three)?

for vSphere 5.x correct answer is A, B and C

Ajay is correct on this one.. http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2014447

The Old Classification Scheme

This classification system applied to ESX 3.0.x, 3.5 and 4.x.

Security – The patches that belong to this category fix one or more potential security vulnerabilities in ESX. Immediately implement security patches to protect your system from these vulnerabilities.

Critical – The patches that belong to this category fix flaws in the product that can potentially cause data loss or severe service disruptions. Immediately implement critical patches.

General – The patches that belong to this category can include fixes for minor flaws, new driver updates, and non-intrusive enhancements. Evaluate general patches to determine if any resolved issues or enhancements benefit your system. Apply these patches as needed.

The New Category/Severity Scheme
Starting with ESXi 5.0, the classification scheme now contains a two-level Category and Severity scheme.

The Category contains these definitions:
1.BugFix – The fix is for a normal product defect.
2.Security – The fix is for security-related product issues.
3.Enhancement – A new hardware enablement, a new driver update or a new product feature is added.
The Severity contains these definitions:
1.For BugFix category

Critical – A problem which may severely impact the customer’s production systems (including the loss of production data). Such impacts could be system down or HA not functioning. A workaround is not in place.

Recommendation: Immediately implement the critical patch.

Important – A problem may affect functionality, or cause a system to function in a severely reduced capacity. The situation causes significant impact to portions of the business operations and productivity. The system is exposed to potential loss or interruption of services.

Recommendation: Immediately plan for a maintenance window for the patch.

Moderate – A problem may affect partial non-critical functionality loss. This may be a minor issue with limited loss, no loss of functionality, or impact to the client’s operations and issues in which there is an easy circumvention or avoidance by the end user. This includes documentation errors.

Recommendation: Implement the patch in your next maintenance window.

Low – A problem is considered low or no impact to a product’s functionality or a client’s operations. There is no impact on quality, performance, or functionality of the product.

Recommendation: Implement the patch at your convenience.

more info in the pdf..