Keyword Strategy for Authority Site

Im trying to create an authority site and adding one quality original 500 words article per day, but Im unsure to which strategy to implement regarding the keywords...

A) Concentrate each article to target 1 keyword

B) Add as many different keywords as possible in each article?

Considering I could produce good articles using strategy A or B, which one do you think would produce better results?

The site provides a specialist service and will be targeting about 100 very low competition kws and exclusively focusing to Spain

As from my experience, it's better to target 1-2 keywords per article, because it won't mess the content up and lets you feature some particular product or service more precisely. If the article is unique and seeks to provide some useful information, I think it will be enough to optimize it for just a few keywords. Moreover, if you plan to update your site frequently, you will cover more keywords over time. On the contrary, if you stuff your article with as many keywords as possible, you can actually lose the quality aspect of it, and this may eventually affect your rankings in a negative way.