At eight paragraphs long, the preamble to the constitution of ______ country in Western Asia—is much longer than the one-
paragraph preamble to the United States Constitution.
Bahrain—a
Bahrain, a
Bahrain a
Bahrain: a
Choice A is the best answer. The convention being tested is the punctuation of a supplementary element within a sentence.
The dash after “Bahrain” pairs with the dash after “Asia” to separate the supplementary element “a country in Western Asia”
from the rest of the sentence. 
Choice B is incorrect because a comma can’t be paired with a dash in this way to separate the supplementary element from
the rest of the sentence. Choice C is incorrect because it fails to use appropriate punctuation to separate the supplementary
element from the rest of the sentence. Choice D is incorrect because a colon can’t be paired with a dash in this way to
separate the supplementary element from the rest of the sentence.