The remarkable persistence of the migrating monarch butterflies through the storms of the southern Rockies ______ continues to puzzle entomologists who study insect navigation.
Which choice completes the text so that it conforms to the conventions of Standard English?
- A
:
- B
;
- C
,
- Dcheck_circle
(empty)
Explanation
A long subject ("The remarkable persistence...Rockies") is not separated from its verb ("continues") by a comma.