Mr. Abul Kashem has set up a pultry firm with investment of TA, 50,000. He gets an average yearly income of TA. 36,000 from the firm, If he did not set up this poultry firm, with this investment he could set up a grocery shop. From such grocery he could get an yearly income of TA. 39,000. What is the opportunity cost of the Poultry firm that Mr. Kashem is running?