All are causes of Clubbing except
Clubbing is due to the proliferation of soft tissue (connective tissue) at the distal end of the fingers
It is a sign of chronic diseases, the commonly supportive and debilitating diseases. diseases like Lung abscess, empyema and bronchiectasis are more important causes with respect respiratory diseases
Long-standing cyanosis also leads to clubbing. mostly seen in cyanotic congenital heart diseases. In question patent ductus arteriosus is a left to right shunt, does not lead to cyanosis until reversal of shunt i.e right to left shunt
Among the choices Patent ductus arteriosus is best to answer.
In Cardia vascular diseases clubbing is due to Infective endocarditis also
Apart from Cardiovascular and respiratory diseases clubbing can be due to endocrine diseases Hyperthyroidism.
There is an idiopathic entity called idiopathic clubbing as well
Remember there is one entity called hereditary clubbing also