Which retailer has shown the maximum increase in its cost per square feet and in which year?

Let us check the option one by one. 

(A) For S. Stop, the increase in cost per square feet in the year 2006 = $$2135-1889$$ = 246

(B) For S. Stop, the increase in cost per square feet in the year 2007 = $$2464-2135$$ = 329

(C) For Pantaloon, the increase in cost per square feet in the year 2006 = $$1996-1729$$ = 267

(D) For Vishal, the increase in cost per square feet in the year 2006 = $$1802-1832$$ = -30

We can see that the maximum increase in its cost per square feet is for S.stop stores in the year 2007. Hence, option B is the correct answer.