Let s represent the number of science majors, m represent the number of math majors, h represent the number of history majors, and l represent the number of linguistics majors.

We can set up the following equations:

s = (1/3)h

m = (2/3)h

s + m + h + l = 2000

We can substitute and isolate the number of linguistics majors.

(1/3)h + (2/3)h + h + l = 2000
2h + l = 2000
l= 2000 - 2h

We can rephrase the question: "How many students major in history?"

(1) SUFFICIENT: If l = m, and m = (2/3)h, we can solve for h:

(1/3)h + (2/3)h + h + l = 2000
(1/3)h + (2/3)h + h +(2/3)h = 2000
(8/3)h = 2000
h = 2000(3/8)
h = 750

If h = 750, l = (2/3)h = 500.

(2) SUFFICIENT: If m = s + 250, and m = (2/3)h and s = (1/3)h, we can substitute and solve for h:

(2/3)h = (1/3)h + 250
(1/3)h = 250
h = 750

If h = 750, l = 2000 - 2(750) = 500.

The correct answer is D.