A. To indicate the directory that include() calls will use as a base.
B. To restrict file open access to a specific directory.
C. To set the working directory.
D. To allow additional file open access than that granted by safe_mode.
Answer B is correct. Answer A is incorrect because the behavior of include() is
unchanged. Answer C is incorrect because the working directory does not depend
on open_basedir. Answer D is incorrect because open_basedir is not affected by
whether safe_mode is enabled.