Daniel’s doctor is trying to determine the cause of his recent onset of asthma symptoms. Of the information Daniel provided, which would his doctor find most helpful in determining a cause?

a.

Daniel had never experienced asthma symptoms until now.

b.

Daniel notices the asthma symptoms occurs more often during cross country practice.

c.

Daniel’s worst symptom is shortness of breath.

d.

Daniel’s sister was diagnosed with asthma at an early age.