I will say studying the referential and grammar parsing really helped me with getting this answer correct. If you properly parse the sentence and identify the referential every answer is eliminated but one!

I got this correct but am really struggling on timing. Took me around 3 minutes before I submitted my answer with full confidence. Does anyone have any advice for how to save time or improve on time?

#help I got all correct but question 3. I confused the necessary and sufficient conditions. I thought the question was trying to determine the necessary premises for one being infected which in that case would be a week has passed and they have produced antibodies. It appears however that the necessary conditions we are supposed to evaluate are one being infected and a week having passed to determine the sufficient value of one producing antibodies. Can someone help me understand how we can are conclusively decided the necessary and sufficient values in this sentence and what techniques are applied here.