Answer:
B. That you had
Explanation:
This is dependent on more, it makes no sense by itself so you need more information for it to make sense.
Gretel changes out her dolls for Nazi posters and when his mom started looking sick. he s also affected when Pavel gets beat up and when he gets yelled at by lieutenant kotler when he likes about Shmuel and makes Shmuel get in trouble
Wouldn't the subject be I because it is about you?
<em /><u><em>"She did not understand what happened."
</em></u>It is a complete sentence since it has a subject (she) and a verb (understand), and is independent (i.e. doesn't require another clause to make sense<u><em>
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