The thirteen original British colonies in North America, some formed

Take another look at (A):

"The thirteen original British colonies in North America, some formed as commercial ventures, others as religious havens, each had a written charter that set forth its form of government..."

We know that "its" must have a singular antecedent, so now we want to scan backwards until we encounter a singular that noun could function logically in place of "its." The first noun we see is "charter," but it wouldn't make any sense to refer to the charter's form for government. A charter can describe a form of government, but it doesn't have one itself. The next singular noun is "each," referring to one of the 13 colonies. Perfectly logical to refer to "each colony's form of government," so we've got our antecedent. Huzzah!

Takeaways: first, we never want to eliminate an answer choice prematurely because of an ambiguous pronoun. (More on that in this video.) Moreover, "its" isn't underlined, so even if we think there's a problem with the construction, we don't have the option of fixing it! Better to focus on the concrete errors we can actually address.

I hope that helps!

E.g "Dave and his friends, who are 20 years old, each has a drivers license" -- doesn't "Dave and his friends" need a verb?

Believe the verb should be have (and not has) because of the plural "Dave and his friends".

So one question EducationAisle. In the above official question, the main subject is The thirteen original British colonies in North America and this one is a plural subject right?

Believe the verb should be have (and not has) because of the plural "Dave and his friends".

The thirteen original British colonies in North America, some formed as commercial ventures, others as religious havens, each had a written charter that set forth its form of government and the rights of the colonists.

(A) some formed as commercial ventures, others as religious havens, each had a written charter

(B) some being formed as a commercial ventures, others as religious havens, all of which had written charters

(C) some that as commercial ventures, others as religious havens, all had written charters

(D) with some being formed as a commercial venture, others as religious havens, all had written charters

(E) with some formed as commercial ventures, while others as religious havens, each had a written charter