5. (6 marks) Let 2 = {a,b,c,d}. Give context-free grammars that generate the following languages. In each case, also give a derivation of the specified terminal string using your grammar. The derivation beginning from the start variable should indicate each individual derivation step using the notation (a) L4 = {a3i+1% +3c2k d2k | i > 0, k > 0} U {a?"b*c*%d"+1 | r > 0,8 >0} Derivation for the string: a-bcd