(i) NFA is more powerful than DFA but DFA is more efficient than NFA.:FALSE
expessing power of DFA=NFA,as no of language accepted by NFA is equal to DFA
(ii) NFA will respond for only valid inputs and no need to respond for invalid inputs.;TRUE
because the is no concept of dead state so if any string with no transition possible will arrive then it will be undefine whch result in assuming that it is not accepted by NFA
(iii) There is no concept of dead states and complement in NFA.:TRUE
(iv) NFA is a parallel computing system where we can run multiple threads concurrently.:TRUE
because it is non determisnistic so can be possible to more the one transition by the same input .