2.
Increased muscle mass tends to produce more stiffness in muscles and joints, requiring frequent stretching.
The correct answer is the date of publication.
All other options do not determine a health source credibility. When it comes to the topic of health, ideas, research, new theories and new discoveries happen constantly so you need to be aware of the date of publication of articles as many will have outdated ideas and research that is no longer relevant. Always check the year of the publication and the more recent the better.
