When the speaker says many businesses are selling me the kitchen sink, he means that they
a) want him to buy everything.
b) want him to buy a new house.
c) sell him items for the kitchen.
d) sell him bath and shower items.

A) Want him to buy everything

Explanation:

Here we have an interesting reference to the idiom everything but the kitchen sink, meaning almost everything possible, whether needed or not. For example, if you wanted to say that someone took too many things with them on a trip, you could say that they took everything but the kitchen sink. The origin of this idiom is not clear.

In this case, the speaker says that the businesses are selling him the kitchen sink, which means that they want him to buy literally everything, even more than what the idiom typically refers to.

the underlined phrase is an example of : understatment

the main character of "the secret life of walter mitty" retreats into a false pretense as a means escape from his mundane reality -- this is a flagrant issue seen in societies abroad, typically found in young adults and it is robbing our youths of their childhood.

explanation:

a thesis -- a well developed, formal thesis is required to be one sentence long. there are many themes in "the secret life of walter mitty" and i had resolved to give you one of the simpler ones while still honing it with class.