语法指代问题Nobody knows exactlyhow many languages there are in th

语法指代问题
Nobody knows exactlyhow many languages there are in the world, partly because of the difficulty of distinguishingbetween a language (and the sublanguages or dialects within it, but those whohave tried to count typically have found) about five thousand.
(A) and the sublanguagesor dialects within it, but those who have tried to count typically have
found
(B) and thesublanguages or dialects within them, with those who have tried countingtypically
finding
(C) and thesublanguages or dialects within it, but those who have tried counting it typicallyfind
(D) or thesublanguages or dialects within them, but those who tried to count themtypically found
(E) or thesublanguages or dialects within them, with those who have tried to counttypically finding
这里C的第二个it为什么不对?OG说应该用复数them