This is a programming principle question. Please let your answer make sense. If your answer is not clear and understandable, I give dislike it. The question that has been asked is only this long, let's specify it as a missing or incorrect comment and don't throw away the solution!

---------------------------

c. Write a grammar for the language consisting of strings that have n copies of the letter a followed by 2n copies of the lett where n > 0. For example, the strings abb, aaabbbbbb, and aaaabbbbbbbb are in the language but a, abbb, ba, and aaabb not