Using pumping lemma, which of the following cannot be proved as ‘not a CFL’?
(a) {a^ib^ic^i|i>=0}
(b) {ss|s∈{a,b}*}
(c) The set legal C programs
(d) None of the mentioned
This question was addressed to me in my homework.
My question is based upon Pumping Lemma for Context Free Language topic in division Properties of Context Free Languages of Automata Theory