Q. Point out the correct statement?

• (A) POSIX represents a portable operating system interface, primarily for UNIX systems
• (B) There are different levels of indication that can be used, ranging from mere notification to fatal error
• (C) The default input format for POSIX dates consists of the month, followed by the year and day, separated by slashes or dashes
• (D) R don't have any way to indicate to you that something's not right