Scientists  / proved / there/ close link/ smoking / lung diseases / such as / cough/ tuberculosis / and worst / all /  fatal canner.

A Scientists  have proved that there is a close link between smoking and lung diseases , such as cough and tuberculosis and the worst of all is fatal canner.

B Scientists  have proved that there has been a close link between smoking and lung diseases , such as cough and tuberculosis and the worst of all ,  fatal canner.

C Scientists  proved that there has been a close link between smoking and lung diseases , such as from cough to tuberculosis and the worst of all is fatal canner.

D Scientists  have been proved that there is  a close link between smoking and lung diseases , such as cough and tuberculosis and worst of all is  fatal canner