Help please !

[Blue_Skies]

Located on the North Sea coast of Scotland, Lauriston Castle was the stronghold of Gregory the Great which was the last one of the Pictish kings.
a) which was the last one of the Pictish kings
b) who was the last one of the Pictish kings
c) who was one of the last Pictish kings
d) who was a Pictish king being the last
e) which was one of the last Pictish kings

[killerdrummer]

IMO C


"who" is used to modify people whereas "which" is used to modify things.(a,e out)

d -> awkward ( being the last)

b -> last one of the X unidiomatic


What is OA???

[aaggar7]

IMO B
Please post the OA

[fcabanski]

The answer is C. Grammar errors trump meaning changes. B has a grammar error. "...last one of the" is not idiomatic. C is the only choice without a grammar error.

[Blue_Skies]

Located on the North Sea coast of Scotland, Lauriston Castle was the stronghold of Gregory the Great which was the last one of the Pictish kings.
a) which was the last one of the Pictish kings
b) who was the last one of the Pictish kings
c) who was one of the last Pictish kings
d) who was a Pictish king being the last
e) which was one of the last Pictish kings

The OA is C. I am confused between B and C. I pick B because 'one of the last' seemed incorrect as suppose to last one. If the sentence is talking about a dynasty such as Maurya dynasty, may be B is correct but i couldn't figure out what the author meant when he says Pictish kings.
Also, i am not sure if last one is incorrect. Ex :

jack,the son of a farmer, was the last one to get a piece of barren land.

Is the above sentence incorrect ?

Thanks !

[fcabanski]

This was just answered in another thread.

A and E use the wrong pronoun.

D is clumsy.

B is improper idiom. "Last of the __________" is English idiom. "Last one of the _________" is not idiomatic.

C is the correct answer. It changes the meaning from "last" to "one of the last", but incorrect grammar trumps meaning on the GMAT. If there are two choices without errors, but one changes meaning, eliminate it. But if all the other choices have grammar errors, as in this case, then go with the one with correct grammar but a change in meaning.