I would have to say parentheses, since its not restricted.
This is C because every other answer doesn’t portray correct pronouns or grammar
Answer:
A single protester attempted to unfurl a banner in the square on June 3, but was quickly arrested by police.
Well, statistics show around half of Americans speak Spanish. So, the people that don't kn it have to learn a language to speak with people that don't know English. Hope this helped!