This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to recognize asthma
Notice any unusual coughing.
Coughing is one of the most common symptoms of asthma. If you cough frequently, even when you're not sick with a cold or flu, you may have asthma.

Choices:
a). Coughing may also be accompanied by a very strong, foul-smelling smell. If you have a strong but very sour feeling to your cough, that may indicate asthma..
b). Take note of your coughing throughout the day and mark when it tends to occur. With asthma, coughing tends to occur often at night..
c). If you experience a sudden chest tightness, abdominal pain, or shortness of breath, you may have asthma. Likewise, feel for any unusual symptoms when you go to the bathroom or change diapers..
d). Notice whether you cough as much or frequently, or if you cough more than usual. Coughing is how mucus runs out of your nose from your airways..
The answer is:
b).