The active phase of normal, relaxed breathing is:

A. Elevated WBC count and increased serum potassium are not common side effects of bronchodilators. These might be seen in other conditions or medications, but not typically with bronchodilators.
B. Nervousness, palpitations, and tremors are common side effects of bronchodilators, particularly beta-agonist bronchodilators like albuterol. These symptoms occur because bronchodilators stimulate beta receptors in the body, leading to increased heart rate and stimulation of the nervous system.
C. Urinary retention and gynecomastia are more commonly associated with other medications, such as anticholinergics or certain hormonal treatments, not bronchodilators.
D. Steven Johnson Syndrome is a rare and severe skin reaction that can occur with certain medications, but it is not a common side effect of bronchodilators.

A. Allergic rhinitis is an allergic reaction to airborne particles like pollen or dust, and while it affects the upper respiratory system, it is not an infection.
B. COPD (Chronic Obstructive Pulmonary Disease) is a chronic condition that affects the lower respiratory system, especially the lungs, but it is not an infection.
C. Tuberculosis (TB) is a bacterial infection that primarily affects the lungs and is considered a lower respiratory infection, not an upper respiratory infection.
D. Acute Coryza is commonly known as the common cold, which is an upper respiratory infection caused by viruses such as rhinoviruses. It affects the nasal passages, throat, and sinuses.