Let Cost of item on store M be x.
Thus, cost of item in store S is 0.9x (10% cheaper)
"Brought from S and saved Rs.100"
This tells us that total price (including Rs.150 of delivery charges) is still Rs.100 less than the price of item listed on store M.( as there are no other charges)
Thus, 0.9x + 150 = x - 100
Solving the equation, we get x = 2500 i.e price on store M is Rs.2500
Thus, Price on Store S is Rs.2250 (10% cheaper than price on X )
Hence, option A.