Which choice completes the text so that it conforms to the conventions of Standard English?
A
unearthed:
B
unearthed,
C
unearthed—
D
unearthed
Explanation
Correct answer: D.
Choice D is the best answer. No punctuation should separate the verb "unearthed" and its objects (i.e, what was "unearthed"): "knives, horseshoes, wool tunics, and thousands of other artifacts."
Why the other choices are wrong
Choice A
Choice A is incorrect. This choice creates a punctuation error, separating the verb "unearthed" from its objects (i.e, what was "unearthed") with a colon.
Choice B
Choice B is incorrect. This choice creates a punctuation error, separating the verb "unearthed" from its objects (i.e, what was "unearthed") with a comma.
Choice C
Choice C is incorrect. This choice creates a punctuation error, separating the verb "unearthed" from its objects (i.e, what was "unearthed") with a dash.