哪位高手帮我解释一下这道数学题？

lly5460

for all x,x is positive integer,"2-height" is defined to be the greatest nonnegative n of x,what is the greatest number of 2-height when 2的n次方 is the
factor of x?
A.2 B.12 C.40 D.76 E.90
答案是C

dancingforum

兄弟, 你贴的题实在是很难懂, 能麻烦你把原来的英文原题贴一下么?
谢了