Answer:
<em>C. the nation, and since then,</em>
Exclamation: If you're joining two sentences together you need a comma to do so. By placing a comma after "nation" and "then" you are making a run-on sentence.
The answer on E2020 is
A. It connects the man to the spade and the act of digging in the dirt.
(I just completed the Test Review with a 100%)
Answer:
dear students at 17 november 2020 we are going to celebrate the annual day. I request you all to practice cultural activities. Thank you for the attention.