Source: GMATPrep Test

Part of the proposed increase in state education spending is due to higher enrollment, since the number of students in public schools have grown steadily since the mid-1980's and, at nearly 47 million, are at a record high

A) enrollment, since the number of students in public schools have grown steadily since the mid-1980's and, at nearly 47 million, are at

B) enrollment, with a number of students in public schools growing steadily since the mid-1980'and, at nearly 47 million, reaching

C) enrollment: since students in public schools have grown steadily in number since the mid-1980's and, at nearly 47 million, have reached

D) enrollment: the number of students in public schools has grown steadily since the mid-1980's and, at nearly 47 millio, has reached

E) enrollment: students in public schools have grown steadily in number since the mid-1980's and, at nearly 47 millio, are at

I chose E, but the correct ans is D. Can the instructors walk through the different ans choices. What role does ":" play in C, D and E.

Thanks in advance.

I think in E meaning changes... The sentence is talking about "growth in the number of students", but E is saying "students have growth"

c is wrong, because you can't follow a comma with a subordinate clause. (if the second part is a subordinate clause starting with something like 'since', it should be introduced with a comma, not a colon.) 'grown steadily in number' is also awkward.

e:
- 'grown steadily in number', as remarked previously, is awkward
- 'at 47m' is a problem, because it seems to modify 'students'. that's illogical: the students themselves aren't 'at 47m' (what would that mean, anyway?) it's the number of students that is at 47m.

in all three of those choices, the colon (:) plays the same role: it introduces an explanatory clause. (notice the use of the comma in the sentence i just wrote)

what is wrong with B

B) enrollment, with a number of students in public schools growing steadily since the mid-1980'and, at nearly 47 million, reaching

B has two issues
1) adverbial clause "with....." incorrectly modifies " spending is"... does not make sense
2) a number of students .. growing... - Students are not growing, the number of students is.

Pathik

good explanation.

let me emphasize: 'a number of students' is incorrect; it has two possible interpretations, neither of which makes any sense:
(1) the idiomatic expression 'a number of', roughly equivalent to 'several' - meaning that several students have gotten fatter and fatter and fatter;
(2) 'a number' of students - meaning some random, arbitrary number of students.
both bad.

I am sorry i didn't understand this. Could you please explain
1. why "with.." is an adverbial clause
2. How is it (incorrectly) modifying "spending is.."

na

1) when prepositional phrases follow commas, they are adverbial modifiers (which modify the action or main verb of the preceding clause)
2) that's the action / main verb of the preceding clause