Help defining the parts of the stimulus

I came across this question:

Newsletter: A condominium generally offers more value for its cost than an individual house because of economies of scale. The homeowners in a condominium association can collectively buy products and services that they could not afford on their own. And since a professional management company handles maintenance of common areas, condominium owners spend less time and money on maintenance than individual homeowners do.

The two portions in boldface play which of the following roles in the newsletter’s argument?

(A) The first is the argument’s main conclusion; the second is another conclusion supporting the first.

(B) The first is a premise, for which no evidence is provided; the second is the argument’s only conclusion.

(C) The first is a conclusion supporting the second; the second is the argument’s main conclusion.

(D) The first is the argument’s only conclusion; the second is a premise, for which no evidence is provided.

(E) Both are premises, for which no evidence is provided, and both support the argument’s only conclusion.

In this question, the correct answer is (A), so the part "condominium owners spend less time and money on maintenance than individual homeowners do" is a sub-conclusion.

I want to know something here

1- regarding the sentence "And since a professional management company handles maintenance of common areas, condominium owners spend less time and money on maintenance than individual homeowners do."

"Since" is supposed to be a Fact indictor, so should the whole sentence be considered a fact/premise or just the part "And since a professional management company handles maintenance of common areas" and the remaining part as a conclusion?

2- and if the bolded statement was "And since a professional management company handles maintenance of common areas, condominium owners spend less time and money on maintenance than individual homeowners do", will we consider this statement a fact or conclusion??