2. Write down the extended regular expression for following questions. E.g. Social security number in the format of 999-99-9999. Answer: [0-91(3)-[0-91(2)-[0-91(4) A Valid URL beginning with "http://" and ending with "edu" (e.g. http://cs.gsu.edu, http://gsu.edu) B Non-negative integers. (e.g. 0, +1, 3320) A valid absolute pathname in Unix (e.g. /home/ylong4, /test/try.c) D Identifiers which can be between 1 and 10 character long, must starting with a letter or an underscore. The following characters can be letters or underscores or digits. (e.g. number,_name1, isOK). E Phone number in any of the following format: 9999999999,999-999- 9999, (999-999-9999. (Note: all of these formats should be matched by a single regular expression) 2. Write down the extended regular expression for following questions. E.g. Social security number in the format of 999-99-9999. Answer: [0-91(3)-[0-91(2)-[0-91(4) A Valid URL beginning with "http://" and ending with "edu" (e.g. http://cs.gsu.edu, http://gsu.edu) B Non-negative integers. (e.g. 0, +1, 3320) A valid absolute pathname in Unix (e.g. /home/ylong4, /test/try.c) D Identifiers which can be between 1 and 10 character long, must starting with a letter or an underscore. The following characters can be letters or underscores or digits. (e.g. number,_name1, isOK). E Phone number in any of the following format: 9999999999,999-999- 9999, (999-999-9999. (Note: all of these formats should be matched by a single regular expression)