The geological formations ______ that line the canyon walls reveal millions of years of sedimentary deposition.
Which choice completes the text so that it conforms to the conventions of Standard English?
- A
,
- B
—
- C
;
- Dcheck_circle
(empty)
Explanation
A "that" clause is restrictive (essential to identifying which formations) and must NOT be set off by a comma. No punctuation between "formations" and "that" is correct.