Best way to join 45 degree window screen stock corners?

[Dennis S]

I am making some 45 X 28 wooden screens for a woman with a 100-year-old house. They are just plain 1.5 X .75 screen window stock. What is the best way to join the 45 degree corners with a minimum of tools? She is sprucing up the house to sell it.

A. Finish nails
B. Dowels
C. Stainless screws
D. Those squiggly things you hammer in

Plus Elmer's, of course.