Siobhan wants to design a Web site for her company, but she is not familiar with usability issues.
Which advice would you give Siobhan regarding usability testing?

A.
Test the site when it is nearly production-ready.

B.
Use a small cross-section of testers for more accuracy.

C.
Do not allow the testers to take notes because this activity will distract them.

D.
Provide assistance at every step of the testing process.