Firefox is an open source program, so anyone can get access to the source code. Which one of the following is something that is possible because Firefox is open source? A: A $5 fee is required to use Firefox. B: Anyone is free to run the compiler to produce and distribute their own version of Firefox.exe. C: Someone can double click Firefox.exe to run it on their computer. D: Someone can run Firefox and note with a stopwatch about how quickly it can draw different web pages.