Specialization makes each of the following possible except:
a.
surplus of goods and services
b.
goods available in a short time frame
c.
variety of goods and services
d.
high-quality goods and services

Specialization does lead to a bigger quality (D) and to a bigger variety (C). It can also lead to a quicker production of goods (B): if each person does only a part of the production, they can do it faster. It  can lead to a surplus, too, if the production is very efficient, but doen't have to and I think that A is the best answer.