The fossil ______ unlike anything previously discovered in the region ______ appeared to belong to a transitional species between two known dinosaurs.
Which choice completes the text so that it conforms to the conventions of Standard English?
- A
, / ,
- Bcheck_circle
— / —
- C
( / )
- D
/
Explanation
Either paired commas or paired em dashes can set off a parenthetical, but the marks must match. Em dashes are appropriate for emphasis.