Construct PDA's that accept the following regular languages.

(a) L = {aⁿ x | n , x{a,b}* and |x| n}

(b) L = {aⁱ b^j | i j 2i}

( c) L = {aⁱ b^j c^k | i , j, k 0 and j= i or j = k}