Countable / Uncountable

[ng27]

When trucks were at the height of their popularity in the late 1970’s, some 20,000 existed in the UK, but today there are less than one-quarter that many.

A. there are less than one-quarter that many
B. there are fewer than one-quarter as many
C. there are fewer than one-quarter of that amount
D. the number is less than one-quarter the amount
E. it is less than one-quarter of that amount

[StaceyKoprince]

please don't forget to list the author of the question; we cannot respond unless the author is posted (and, actually, we will have to delete the question entirely if the author isn't cited...)