Which of the following statements is correct in reference to the important port towns during the 19th century?

a- Calcutta, Bombay and Madras supplied raw materials for industry in England and had emerged because of modern economic forces like capitalism

b- The majority of the working population in these cities belonged to what economists classify as the manufacturing sector. 

Only statement a is correct.

Although Calcutta, Bombay and Madras supplied raw materials for industry in England and had emerged because of modern economic forces like capitalism, their economies were not primarily based on factory production. The majority of the working population in these cities belonged to what economists classify as the tertiary sector.
There were only two important "industrial cities": Kanpur, specialising in leather, woollen and cotton textiles, and Jamshedpur, specialing in steel.