Final answer:
A powerlifter is disqualified from the deadlift for intentionally "dumping" the bar, as opposed to using the "Sumo" style, missing lifts, or using chalk, which are not disqualifying actions.
Step-by-step explanation:
In the sport of powerlifting, a lifter can be disqualified from the deadlift for several reasons. However, the options provided include only one disqualifying action. A lifter would be disqualified for intentionally "dumping" the bar as determined by the majority of judges on that platform (option b). This refers to releasing the barbell in an unsafe manner, either out of frustration or to avoid injury without following proper protocol. Attempting a "Sumo" style deadlift is not a cause for disqualification as it is a legitimate technique (option a). Missing most of their lifts does not result in disqualification; it would only result in a failed attempt (option c). Additionally, putting chalk on the lifter's hands is allowed to improve grip and is not a disqualifying action (option d).