speculation , conspiracy theories or , at best , 
(ROOT (NP (NP (NN speculation)) (, ,) (NP (NN conspiracy) (NNS theories)) (CC or) (, ,) (ADVP (IN at) (JJS best)) (, ,)))
(ROOT (NP (NP (NN )) (, ) (NP (NN ) (NNS )) (CC ) (, ) (ADVP (IN ) (JJS )) (, )))