Nhận biết (M1)

Vilnius, the capital of Lithuania, has a population of 556,723, which accounts for 18.83 percent of the country’s total population. Having proportionally large populations __________ common for national capitals.

Which choice completes the text so that it conforms to the conventions of Standard English?

• A.

  are

• B.

  is

• C.

  were

• D.

  have been