People who are confused what's going on in this question please refer this
Option A is wrong as right hand side can produce null string while left hand side cannot.
Now coming to answer B , there can be 2 situation with this
1. Mistake in presenting option B
Option given there is wrong as (r*s*) cannot generate rsr
2. Answer will be correct if we have (r*s*)* =(r+s)* you can refer Ullman section 3.4.6
3. If we think like this option B can be correct
(r*s*)=(r+s)*
Taking closure on both the sides we get
(r*s*)*=((r+s)*)*
We know thst (a*)*= a* check identities
Hence (r*s*)*= (r+s)*
Others please check if my third interpretation is valid and correct me if I am wrong .
@Arjun, @Sreshta