1. show that the following languages are context-free. you can do this by writing a context free grammar or a pda, or you can use the closure theorems for context-free languages. for example, you could show that l is the union of two simpler context-free languages. (a) l = 0 n12n (b) l = {0, 1}* - {0 n1 n : n ≥ 0} (c) l = {0 m1 n2 p3 q : n = q, or m ≤ p or m + n = p + q} (d) l = {0, 1}* - l1, where l1 is the language {1010010001…10n-110n1 : n n ≥ 1}.