CSR .

The above answer is correct because qualified expenditure by csr on three years average profits is

• Eradicating extreme hunger and poverty
• Promotion of education
• Promoting gender equality and empowering women
• Reducing child mortality
• Improving maternal health
• Combating human immunodeficiency virus, acquired, immune deficiency syndrome, malaria and other diseases
• Ensuring environmental sustainability, 
• Employment enhancing vocational skills, social business projects
• Contribution to the Prime Minister’s National Relief Fund or any other fund set up by the Central Government or the State Governments for socio-economic development, and
• Relief and funds for the welfare of the Scheduled Castes, the Scheduled Tribes, other backward classes, minorities and women and such other matters as may be prescribed.

One off means an event which occurs to not once 

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