Sentence Correction

IMO D.

Supposedly is an adverb, adverb cannot modify noun...in question first northern american colony is noun..so all option including supposedly are wrong..eliminate A, B, E

left are C and D...here both ' as old as' and 'older than' are idiomatic...in this case only way to eliminate is to check whether 'as old as' fits or 'older than' ..one can straightway tell that it is D which fits in this context..

C is wrong because you will always say 'x is as old as y' where x and y are parallel. but question states '600 years as old as first north american colony'

OA plzzzzzz...

oa is B thanks every body for active participation