11) A marketing research firm would like to survey undergraduate and graduate college students about whether or not they take out student loans for their education. The survey cost (for each student) is provided below: Region Undergraduate Graduate East $10 $15 West $15 $20 The marketing research firm would like to minimize the cost of the survey while meeting the requirements. Let X1 be the number of undergraduate students from the East region, X2 is the number of graduate students from the East region, X3 is the number of undergraduate students from the West region, X4 is the number of graduate students from the West region. One of the survey requirements is: at least 40% of the graduate students surveyed should be from the East region. Which of the following correctly formulates this constraint? A) 2X1 + 3X2 + 3X3 - 6X4 = 0 B) 2X1 - 5X2 + 2X3 = 0 C) 2X2 - 3X4 2 0 D) 3X2 - 2X4 2 0 E) None of the above