Ace Test Series: Compiler Design - Grammar

Question

Is the following question even valid? Shouldn't there be a production for all variables?

Comments

As from X we can never end a parse tree as there's no production for S... so just remove that production.
Actually here the question is asking us to remove unneccessary productions .
So correct answer will be c only i.e Z --> 0 [reduced cfg] as Z--> X never ends due to S variable missing production.

Answer 1

option C seems correct,

please read reduction of CFG

1. removing null , use productions

2. use less symbols ( S in this case )

3. unit productions