please help

All string that starts and ends with a different symbol: O a (a+b)* b + b (a+b)* b O a (a+b)* b Ob (a+b)* a b (a+b)* b All strings that starts with ab and ends with ba is: None of the above ab a*b* ba ab (a+b)* ba b ab (ab)" ba A language, L = + a + aa + aaa + ..., is represented by a* a+ (a+b)* None of the above The regular grammar, A ==> O A | 1 A TE generates 0*12 1 0 (0+1)* 0 0 + 1 None of the above The regular grammar, A ==> OB | 1B B ==> OC | 1C C ==> generates O All strings that has string length 1 All strings that has string length > 3 All strings that has string length 2 All strings that has string length 3