If gonorrhea is a treatable infectionwhy do so many men experience severe damage and infertility or joint infections as a result of leaving it untreated

Gonorrhea is treatable, but that doesn't mean it treats itself. Just like cancer, pneumonia, etc., gonorrhea needs medicinal treatment and if that treatment never occurs the consequences can be devastating. 

The answer is C. Stress isn't always unhealthy. Not all stress is harmful. Positive stress is called eustress. It results in positive results or feelings. For example, playing the piano in a recital can cause stress, but it is a very positive experience when you do well because everyone applauds and you are proud yourself. You may have felt nervous while you waited to perform, but you probably knew it was going to be a good experience. 
So the answer is C,Stress is always unhealthy and should be avoided. 

I hope this helps!