Answer:
A fitness training blog
Step-by-step explanation:
In the field of science and technology, health and fitness, the most reliable source to get authoritative data is the articles published related to them. As articles are thoroughly tested by experiments and are also subjected to peer review hence, these steps prove them to be the most reliable source of data.
On the other hand, blogs are not authentic as they are not subjected to any checks on them. The writer just tend to gather data or sometimes add up on their own and publish it. Hence, a fitness training blog is the least authoritative data on health and wellness.