**Core Concept:** Respiratory rate is the number of breaths per minute in a healthy individual. In infants, respiratory rate is influenced by age, body size, and environmental factors. Tachypnea is defined as respiratory rate exceeding a certain threshold for age.

**Why the Correct Answer is Right:** In a 2-month-old infant, a respiratory rate greater than 60 breaths per minute is considered tachypnea. This is because respiratory rate is influenced by age, with infants having a higher normal rate than adults. Additionally, the rate should be adjusted for body size, as larger infants may take longer to breathe.

**Why Each Wrong Option is Incorrect:**

A. 60 breaths per minute: This is the correct normal respiratory rate for a 2-month-old infant, but it is too low for the correct answer to be correct.

B. Infection: Tachypnea is not exclusively caused by infections. It can be seen in various conditions, as explained in the explanation.

C. Hypoxia: Hypoxia is the decreased oxygen supply to body tissues, not a cause of tachypnea. Tachypnea is a response to hypoxia or other causes.

D. Asthma: Although asthma can cause tachypnea, it is not the only cause. Tachypnea can be due to various respiratory and non-respiratory conditions, as explained in the explanation.

**Clinical Pearl:** Tachypnea in infants should prompt a thorough evaluation to identify the underlying cause. Common causes include respiratory infections (e.g., pneumonia), congenital heart disease, asthma, pulmonary hypoplasia, and pulmonary hypertension. Additionally, consider the influence of environmental factors, nutritional status, and body size. A timely intervention can prevent complications, such as hypoxia and respiratory acidosis.