4. (4 marks) Use left-factoring and/or eliminate left-recursion to transform each of the below eight grammars into a form that is suitable for recursive-descent parsing. As usual capital letters denote variables and lower case letters are terminals. (a) S + dbSc | dbaSa cbda | baa (b) S + Sbc | Sab | ac | Sdc (c) S + Saba Scc (d) S ccdbSa | dcaSb | ccbSa E (e) S + bbcSa cSa bbcad | dca (f) S + SA E A + Ab a (g) S abcSd | cdads | cdabs | abb (h) S + Sab | Sac | 6 | 0 Hint for (h): Here after elimination of left recursion you need to use also left-factoring (or vice versa)