|Question 18Verbal

Source Texts

Text
The Proto-Atlantic-Congo language, common ancestor of 1,453 African languages with similar linguistic properties, _____ like all protolanguages, hypothetical: there's no direct evidence these ancestral languages actually existed.
Which choice completes the text so that it conforms to the conventions of Standard English?
were,
A
is,
B
are,
C
have been,
D