Which one among the following statements appropriately defines the term 'drain theory' as propounded by Dadabhai Naoroji in his work 'Poverty and un-British Rule in India'?

• A. That the resources of India were being utilised in the interest of Britain
• B. That a part of India's national wealth or total annual product was being exported to Britain for which India got no material returns
• C. That the British industrialists were being given an opportunity to invest in India under the protection of the imperial power
• D. That the British goods were being imported to India making the country poorer day by day