Unlike other retail outlets, where items are purchased in any number of units the customer wants, in super - markets items are grouped in bulk packages. This bulk buying offers savings to the customer. The option to buy at wholesale prices by buying in bulk makes super - markets a practical choice for budget - conscious consumers.
Which of the following is an assumption necessary to the author’s argument?

The argument states that supermarkets are a practical choice for budget-conscious consumers because they offer savings through bulk buying. However, one potential drawback of bulk purchasing is that customers cannot buy exactly the quantity they need.

For the argument to hold, the author must assume that the savings from buying in bulk are significant enough to make up for this inconvenience. If the inconvenience were greater than the savings, supermarkets would not necessarily be a practical choice. Therefore, Option E is a necessary assumption. 

Option A: This talks about variety and overhead costs, which are unrelated to the author's argument about savings from bulk buying.

Option B: This mentions convenience and parking, which are not part of the author's reasoning for why supermarkets are a budget-conscious choice.

Option C: This talks about competition and small retail store closures, which are not relevant to the argument about customer savings.

Option D: This contradicts the argument by stating that bulk buying seldom offers savings, which goes against the author's claim that supermarkets are a practical choice for budget-conscious consumers.