Which choice completes the text so that it conforms to the convention…

Source Texts

Text

When documenting butterfly diversity at Rupa Lake in Nepal, researcher Alyssa B. Stewart and her colleagues spotted a very rare butterfly of the Hesperiidae family and, after careful examination, knew exactly what species it belonged blank Ochus subvittatus.

Which choice completes the text so that it conforms to the conventions of Standard English?

to and

to:

to;