4. Prove that there is no ternary code C with |C|| = 29 such that C has length 9 and corrects 3 errors. 5. Prove that there is a binary code C with |C| 4 such that C has length 12 and corrects 2 errors. 6. Is there a ternary code C with |C|= 20 such that C has length 11 and corrects 2 errors? Justify your answer.