UGC NET CSE | December 2005 | Part 2 | Question: 4

Question

Which sentence can be generated by $S\rightarrow d/bA, A\rightarrow d/ccA$ :

• A. $\text{bccddd}$
• B. $\text{aabccd}$
• C. $\text{ababccd}$
• D. $\text{abbbd}$

Answer 1

The set of strings generated by given grammar starts with either d or b.

So straight away options B,C,D are eliminated.

Let us try to derive $bccddd$.

$S\rightarrow bA\rightarrow bccA\rightarrow bccd$.

$\therefore$ String $bccddd$ can't be generated from given grammar.

So option A is eliminated.So none of the options are correct

Answer 2

(A) bccddd ...

 

The most closest answer seems to be A only.

The terminals in the grammar are d,b and c...

There is no terminal 'a' at all.

So the options B,C and D are ruled out...

option A can also be derived at something like this.

S->bA ->bccA ->bccccA ->bccccd

So the sentence generated should be bccccd. If there are any other explanations for the same please post them.…