What is the average rate of change in the cost per square feet of the retail sector, if the sector is represented by the above four retailers in the period FY07 to FY10E?

The cost per square feet of the retail sector, in the year 2007 = 2044+2464+1751+1525 = 7784

The cost per square feet of the retail sector, in the year 2010E = 1396+2230+1064+1051 = 5741

Therefore, What is the average rate of change in the cost per square feet of the retail sector for the given period = $$\dfrac{\dfrac{5741-7784}{7784}\times 100}{3}$$ = $$-8.74$$ percent. Hence, option D is the correct answer.