Sentence Correction (SC) | Re: The recent spate of traffic jams on Beijing-Tibet highway

Yes, certainly 'because of' is a better expression than 'due to'. However, since 'due to' is appearing in all the five choices, one might look at the other aspects of the topic and see if one can take away something.
The main intent of the topics was to unnerve test takers with monstrous verbiage but indicate that simple things like SV and fragmentation could be of much help.