Choose the correct option to fill ? 1 and ? 2 so that the program below prints an input string in reverse order. Assume that the input string is terminated by a newline character.

void recerse (void) {
  int c;
  if (?1) reverse() ;
  ?2
}
main {
  printf ("Enter Text" ); 
  printf("\n");
  reverse() ;
  printf("\n") ;
}

Which of the following are true?

I. A programming language which does not permit global variables of any kind and has no nesting of procedures/functions, but permits recursion can be implemented with static storage allocation

II. Multi-level access link (or display) arrangement is needed to arrange activation records only if the programming language being implemented has nesting of procedures/functions

III. Recursion in programming languages cannot be implemented with dynamic storage allocation

IV. Nesting procedures/functions and recursion require a dynamic heap allocation scheme and cannot be implemented with a stack-based allocation scheme for activation records

V. Programming languages which permit a function to return a function as its result cannot be implemented with a stack-based storage allocation scheme for activation records

Which of the following are decidable?
$$1.$$ Whether the intersection of two regular languages is infinite
$$2.$$ Whether a given context-free language is regular
$$3.$$ Whether two push-down automata accept the same language
$$4.$$ Whether a given grammar is context-free

Which of the following statements are true?
$$1.$$ Every left-recursive grammar can be converted to a right-recursive grammar and vice-versa
$$2.$$ All ε-productions can be removed from any context-free grammar by suitable transformations
$$3.$$ The language generated by a context-free grammar all of whose productions are of the form $$X \to w$$ or $$X \to wY$$ (where, $$w$$ is a string of terminals and $$Y$$ is a non terminal), is always regular
$$4.$$ The derivation trees of strings generated by a context-free grammar in Chomsky Normal Form are always binary trees