Sorry this is late but here is the answer...
Answer:
Store B.
Step-by-step explanation:
Kala's family will get more of a discount at store B. Store B has the 10% off while the competitor stores gave "weaker" deals. Store D has a $40 rebate with a tax. So her family won't go there. Rebates aren't the best option because you have to pay the full amount by a certain time where as a discount, you pay everything there on time. So, the answer is B. I hope this helps.