Which tool should use?

You are piloting the deployment of a SharePoint Server 2010 Service Pack 1 (SP1) server farm named Farm1. Farm1 contains two front-end Web servers and an application server. You create a new site collection that contains five sites. You need to simulate 200 user connections to the sites. The solution must use the minimum amount of administrative effort.
Which tool should use?
A. Stsadm
B. Microsoft SharePoint Designer
C. Test-Connection
D. Microsoft Visual Studio

Correct Answer: D
Explanation/Reference:
To determine how well your software responds to various levels of usage, you conduct load tests. A load test models the expected usage of a software program by simulating multiple users who access the program at the same time.

http://msdn.microsoft.com/en-us/library/dd293540.aspx