A – Wrong
The text clearly says ‘If this study is to be believed’. This shows that the text is unsure whether the new study is more accurate than the old study.
B – Wrong
The text does not suggest this at all. The new study suggests that cancer can be caused by extrinsic factors but the text is unsure whether the new study is accurate or not.
C – Wrong
The text does not suggest any cancer prevention methods. So this is irrelevant.
D – Correct
The last sentence ‘…to a significant extent within your control’ suggests that the text is assuming people have control over extrinsic factors.