The parent of a 1-year-old child with tetralogy of Fallot asks the nurse, "Why do my child's fingertips look like that?" On what understanding does the nurse base a response?

Clubbing occurs as a result of decreased cardiac output.

Clubbing occurs as a result of a left-to-right shunting of blood.

Clubbing occurs as a result of chronic hypoxia

Clubbing occurs as a result of untreated congestive heart failure.