Answer:
 Most customers who rate their service as high quality return for additional meals. 
Explanation:
Only some customers who rate their service as high quality return for additional meals. - its not this because it says only SOME and 90% is not some it is MOST but not all. 
High quality services cause customers to return for additional meals - just because the restaurant has high quality service that doesn't mean that this causes them to come back for an additional meal.
 
Customers who will return for additional meals report a high quality of service. - its not this because it just doesn't make sense.