1. for each case below, decide whether a given language is a cfl, and prove your answer by constructing a pda or using the pumping lemma. a. l = { x { a, b, c }* | na(x) < nb(x) and na(x) < nc(x) }, where ni(x) is the number of occurrences of symbol i in x. b. l = { xayb | x, y { a, b}* and |x| = |y| } c. l = { xcx | x { a, b}* } d. l = { x{ a, b, c}* | na(x) = min(nb(x), nc(x)) } e. l = { w | w { a, b, c }*, numc numa + numb } f. l = { 0i1j | 2j i 4j }