The correct option is option D ("Read the results section before you read the discussion section").
Taking a look at the results before you read the discussion section will allow you to form your own interpretation after analysing the content of the article without being biased by what the author's conclusion was in light of the results.
Here's my interpretatin of why the other options are wrong:
A) You should always start with the introduction and never with the abstract. If you first read the abstract, you run the risk of becoming biased towards the author's perspective from the get go.
B) & C) The discussion and conclusion sections should always be the last thing you read. You need to understand the whole article by yourself and generate your own interpretation to be able to contrast it with the author's conclusion and other points of view expressed in the discussion.
Hope this helps!
