It is the velocity of the object.
A beta particle. Hoped I help. Sorry if it wrong.
A is only the area of one tile. It wants the area of the whole floor.
area of parallelogram is b*h=0.952. There are 9500 of them so 0.952*9500=904.4 (answer c)
D. There's not enough research surrounding it. A big question is if they have side effects due to genetic modification that we don't know of.
(Not sure if you had D eliminated or? But it should be the correct answer)