Answer:
x=y<z, option B is correct.
Step-by-step explanation:
Lets calculate how much money the stores charge with respect to the price list.
Since Z does not charge with taxes or discounts, then Z sells 100 % the price list.
X applies a discount first, so it sells at 95% the price ignoring taxes. With the tax charge it increases by a 5% of the 95, so in total it sells with 95 + 95*(0.05) = 99.75 %
Y charges with taxes first, so it the prices increases by a 5% to a total of 105% the list price, and then makes a discount, so the total price is 105-105*0.05 = 99.75%
As a result
x = 99.75%
y = 99.75%
z = 100%
Therefore x=y<z. Option B is the correct one