Direction: Choose the statement(s) or part(s) thereof that has/have an error of grammar or syntax.

(A) The company is investigating a case where a curious passenger (B) had brought a sub-way train to a halt by pulling the emergency brake in one carriage, (C) thus putting all the passengers to risk because the doors of the train opened easily (D) during the emergency stop and passengers could be jostled out of the moving carriage.