Go for smoke Testing  in this case

If there is not enough time for testing i think Adhoc 
testing is better.

HI

  When Time Limits Go for
   Smoke Test
   Monkey Test
   Ad-hoc Test


  sun_ramprasad@yahoo.com

in this type of situation we test the application's main 
functionality which is most important in business point of 
view.

  we concentrate on the the application where the defects 
found in previous similar application.

Then prioritize the test cases.
execute those test cases having higher priority.

i did face this question in my interview and i did give them
the answer " depending on critical impact risk i would
prioritize the test cases and then execute the test cases
having high priority." but it seemed like they were not
happy with such a short answer. my be the answer should be a
bit more detailed like below:
When facing a short time frame available for testing
purposes, you got to make the best the time and resources
available. A software test strategy that takes this into
account is risk and requirements based testing.
In this strategy we assume that it's not possible to test
everything.Risk and requirements based testing helps you to
determine what to test first, in which sequence, so you
spend the time you have to the parts that really matter.
The strategy starts with a risk analysis to determine the
functions (requirements) with the highest risk, and plan
your test activities guided by this analysis.
To help you identify the risks involved in all your
requirements, consider the following aspects:
•Functions often used by the users
•Complex functions
•Functions that have a lot of updates or bug fixes
•Functions that require high availability
•Functions that require a consistent level of performance
•Functions that are developed with new tools
•Functions that require interfacing with external systems
•Functions with requirements with a low level of quality
•Functions developed by more programmers at the same time
•New functions
•Functions developed under extreme time pressure
•Functions that are most important to the stakeholders
•Functions that reflect a complex business process