4. For the following relation: Articles (ID, title, journal, issue, year, startpage, endpage, TR-ID) It contains information on articles published in scientific journals. Each article has a unique ID, a title, and information on where to find it (name of journal, what issue, and on which pages). Also, if results of an article previously appeared in a "technical report" (TR), the ID of this technical report can be specified. We have the following information on the attributes: For each journal, an issue with a given number is published in a single year. The endpage of an article is never smaller than the startpage. There is never (part of) more than one article on a single page. The following is an instance of the relation: ID 42 33 Deterministic Dictionries JAg41 33 Deterministic Dictionaries JA1g41 2001 69 39 Dictionaries in less space SICOMP 31 2001 111 57 title Journal issue year startpage endpage TR Cuckoo Hashing JA1g 51 2004 121 69 133 87 85 85 133 47 62 P vs NP resolved What Gdel missed What Gdel missed JACH 2008 SICOMP 51 2008 Nature 2222 2008 5 98 98 78 Questions: a) What is the primary key for Articles. b) For each of the following potential functional dependencies (FD), indicate whether it is indeed a FD or not. 1). ID title; 2). startpage endpage; 3). (journal, issue) year 4). title ID; 5). ID startpage, endpage, journal, issue; 6). TR-ID ID c) Based on a) and b), perform normalization into BCNF, and state the resulting relations