C. Was
It says "my parents or my older sister". The last subject stated is "my older sister" which is singular. And the only choice that's singular is 'was'. So that should be the answer.
The dark cloud was like a stain of darkness over the wide-open plain.
(Is that too advanced?)
There was a red stain on the boy's shirt as he stood in the grassy plain.
(That's a bit simpler.)
The answer would be D because colons go before lists and the word run started the list of the errands
<span>The answer is "Hiding in the tree fort he had built as a kid." The first one.</span>