You have asked 2 questions:
Dynamic vs. Static
So to answer your question from a purely technical standpoint, the spider cannot tell the difference.
Some SEO experts (Disclosure: my feelings on SEO are a matter of public record on my blog) feel that SEF URLs are important. Therefore in your example #3 would be the best if you were selling tests.
I am firmly ambivalent on SEF URLs as my testing has shown to my satisfaction that it makes little or no difference these days.
However, from a human readable standpoint:
is much better than
If it's not too much trouble to do it then it pays off because your users can actually read and make sense of the URL. (In WordPress and Joomla! it's not difficult at all to get User Friendly URLs.)