Where S is the start symbol, S$,$ A$,$ B$,$ and C are the non$-$terminals and $,,$ and $$ are the terminals. For

each of the following indicate if $(0)$ the input has no parse tree according to the grammar, $(1)$ the input

has one unique parse tree according to the grammar, $(2)$ the input has only two parse trees according

to the grammar or $(3)$ the input has three or more parse trees.

$1.$ a a b b b b b b b c

$2.$ a a b b b b c c d

$3.$ a a b b c c c c d

$4.$ a a a b b b b b b c c c c c c d