even if OA is A,the answer is wrong.I'm a student of Knewton.I sent this question to knewton and got the following explanation.
MY QUESTION
Since 1966, roughly 21 percent of those enlisted in the USMC had reached
an E-5 ranking in fewer than three years.
(A) had reached an E-5 ranking in fewer than three years
(B) have reached an E-5 ranking in less than three years
(C) have reached an E-5 ranking in under three years
(D) had reached an E-5 ranking in less than three years
(E) have reached an E-5 ranking in fewer than three years
Obviously A and D are out for using wrong tense because Since... can be
followed only by present perfect , as in B,C,and E.
Now I'm stuck (less than vs fewer than). I know that I can count years (1
year , 2 year etc) , but the following usage of fewer than (Oxford
dictionary) does not agree.
https://www.oxforddictionaries.com/page/150
People often don't know when to use *less* and when to use *fewer* in a
sentence. Here's how to get it right.
Use *fewer* if you're referring to people or things in the plural (e.g. *
houses*, *newspapers, dogs*, *students, children*). For example:
People these days are buying *fewer newspapers*.
*Fewer students* are opting to study science-related subjects.
*Fewer* than thirty *children* each year develop the disease.
Use *less* when you're referring to something that can't be counted or
doesn't have a plural (e.g. *money*, *air*, *time*, *music*,*rain*). For
example:
It's a better job but they pay you *less money*.
People want to spend *less time* in traffic jams.
Ironically, when I'm on tour, I listen to *less music*.
*Less* is also used with numbers when they are on their own and with
expressions of measurement or time, e.g.:
His weight fell from 18 stone to *less* than 12.
Their marriage lasted *less* than two *years*.
Heath Square is *less* than four *miles* away from Dublin city centre
This explanation also then justifies the usage " I have less than two
dollars" and not " I have fewer than two dollars" because dollar is an
expression of measurement and two is a number. Please clarify.
THEIR REPLY
The OED's explanation is correct. An easier way to remember this is that "fewer" is for countable nouns, and "less" is for uncountable nouns with three exceptions: money, time, and distance (for which we use "less"). So we say "The event lasted less than two hours" and "I have less than two dollars in my wallet" and "Time ran less than two miles this morning" because these are all nouns describing time, money, or distance. Otherwise, we use "fewer" with countable nouns, even countable nouns preceded by a number. For example, "The class has fewer than 100 students."
The correct answer to this question should be choice B: "have reached an E-5 ranking in less than three years." We need "less" because "three years" is a measure of time. "I have less than two dollars" is also the correct expression because "two dollars" is a measure of money.
Note that not every noun preceded by a number takes "less." For example: "There are fewer than 10 students in the class." This is correct because "students" is not an expression of measurement, time, money, or distance. The number "10" is basically just further proof that "students" are countable. So we use "fewer."
GOT IT GUYS?
THE ANSWER SHOULD BE B.
Infact you can even check MGMAT strategy guide to confirm that have ALWAYS goes with phrases " Since...", "From.."
Also, MGMAT guide says you can say :
I have less than ten dollars
But you cannot say : I have fewer than ten dollars.
Instead if you have to use fewer you say:
I have fewer than ten dollar bills.
