Yesterday, a question was put forth to Oppo.
The answers from the question were totaled up at midnight Central time, and compiled into a graph. On posts with multiple answers, (i.e. "B or A"), only the first answer was counted. This graph answers the question once and for all: Is it a hand truck, is it a dolly, or is it called something else?
The answer, by a slim margin, is Hand Truck!
(If you're wondering who said "corpse mover", it was Nibby.)
I would be curious to see a regional breakdown of "Hand truck" vs. "Dolly", but that data wasn't available at the time.