For the given question
1st statement is false because power of NFA=power of DFA and both are unambiguous therefore the ambiguity cant be occur due to NFA
2nd statement is that ambiguity of cfg is due to NPDA it could be true because the power of NPDA is superset of DPDA therefore every cfg is a NPDA can accept the ambiguous grammar
3rd statement is always true because anyway every regular expression is unambiguous only
it is dependent on language that whether it accepts the ambiguous grammar or not.