C. Sensitivity
because this isn't a constant thing, so it isn't a. it isn't b. and it isn't d.
Yea I have why u asking that
I don't exactly know how to put this in scientific terms, but it is a wet cough which when completed, has brought up phlegm enough to fill a handkerchief. It is the last stage of a common cold before it goes away.
It can be challenging because you have to learn at there pace when you have your own pace of working
