3. [12 marks] This question develops your ability to design CFGs. For each of the following languages, give a CFG. Assume the alphabet is -(0,1). Justify your answers briefly. (a) {x | x starts and ends with different symbols). (b) {x | the length of x is odd). (d) {x | x does not contain any substrings of zeroes of odd length). For example, e, 100, 000011100 are in the language, but 01100 is not. 4. [12 marks] This question develops your ability to design PDAs. For parts (a). (b). (c) of question 3 above, give state diagrams of pushdown automata. For each automata, include a brief description of the idea behind its design