<prompt>  A two-month-old infant is brought to the hospital emergency with marked respiratory distress. On examination, the infant has cyanosis and bilateral crepitations. Heart rate is 180min, respiratory rate 56min and the liver span 7.5 cm. The child has had repeated episodes of fever, cough and respiratory distress since the time of birth. Cardiovascular examination reveals a grade III ejection systolic murmur in left parasternal area and the chest X-ray reveals cardiomegaly with a narrow base and plethoric lung fields. What is the most likely diagnosis ?Congenital methemoglobinemiaTransposition of great arteriesCystic fibrosisTetralogy of Fallot 