Answer:
<h2>C. The hiker followed the north trail a distance of two kilometers in thirty minutes.</h2>
Explanation:
This sentence completes a scientific description because it specify the variables involved: distance and time.
Also, direction is other variable that is involved and also explained, when it says<em> ''the north''.</em>
It's important to say that in science, the terms used in writing activities needs to be technical, it has to be an objective language, otherwise, arguments are not valid.