Use the pumping lemma to show that the following languages are not regular.

^Aa. A₁ = {0ⁿ1ⁿ 2ⁿ| n ≥ 0}

b. A₂ = {www| w ∈ {a, b}^*}

^Ac. A₃ = {a²ⁿ| n ≥ 0} (Here, a²ⁿ means a string of 2ⁿ a’s.)