Pastor Richard Obwar has bought a twenty-acre piece of land in Ukwala, Siaya District. The area is suitable for growing Maize, Sweet potatoes, and Cassava. Obwar wishes to grow only one of the crops for ease of management since he wants to continue living in Nairobi, where he is a full time pastor at Friends of Christ Church. In the process of making a choice, he gets access to records of three farmers, each with a twenty-acre piece of land. One of the farmers had 6 acres of Maize, 8 acres of sweet potatoes, and 6 acres of cassava and received an average of sh. 396,000 annual earnings. The second farmer had 8 acres of maize, 6 acres of sweet potatoes, and 6 acres of cassava and received sh. 394,000 average annual earnings. The corresponding figures for the third farmer were 8, 8, 4 and sh. 400,000. Based on this information, which crop should Obwar grow on his shamba and what would be the expected annual earnings.