it is one in which fear and frustration are provoked to intolerable levels 
(ROOT (S (NP (PRP it)) (VP (VBZ is) (NP (NP (CD one)) (SBAR (WHPP (IN in) (WHNP (WDT which))) (S (NP (NN fear) (CC and) (NN frustration)) (VP (VBP are) (VP (VBN provoked) (PP (IN to) (NP (JJ intolerable) (NNS levels)))))))))))
(ROOT (S (NP (PRP )) (VP (VBZ ) (NP (NP (CD )) (SBAR (WHPP (IN ) (WHNP (WDT ))) (S (NP (NN ) (CC ) (NN )) (VP (VBP ) (VP (VBN ) (PP (IN ) (NP (JJ ) (NNS )))))))))))