The staple commodities of export by the English East India Company from Bengal in the middle of the 18th century were

Correct Option: (d) Cotton, silk, saltpetre and opium

During the mid-18th century, the principal commodities exported by the English East India Company from its flourishing trade base in Bengal included cotton textiles, raw silk, saltpetre (potassium nitrate, vital for gunpowder), and opium. These items formed the bedrock of the Company's lucrative export trade to Britain and other markets. Therefore, option (d) is correct.