The argument made in the text is the last line. “So it’s clear that someone who is awarded a PhD in Sweden will live longer…if they had not studied for a higher degree”.
We must find a flaw in this sentence.
A – Correct
The census is only for people aged 64. The above argument generalises people aged 64 with ‘someone’. Hence this is the flaw.
B – Wrong
No mention of healthy lifestyles in the text.
C – Wrong
No mention of other countries in the sentence above. It specifies Sweden.
D – Wrong
Nothing mentioned about the health of people who are awarded PhD.