Which retailer shows the sharpest decline in cost per square feet and in which year?

Let us check the option one by one. 

(A) For Westside, the decline in cost per square feet in the year 2005 = $$2411-1724$$ = 687

(B) For Pantaloon, the decline in cost per square feet in the year 2008 = $$2044-1656$$ = 388

(C) For S. Stop, the decline in cost per square feet in the year 2009 = $$2419-2197$$ = 222

(D) For Vishal, the decline in cost per square feet in the year 2010 = $$1659-1064$$ = 595

We can see that the sharpest decline is for Westside stores in the year 2005. Hence, option A is the correct answer.