Final answer:
The Enterobacteriaceae family consists of gram-negative rods that can ferment glucose and sometimes lactose; they can be motile with peritrichous flagella. However, gram-positive bacteria are not part of the Enterobacteriaceae family.
Step-by-step explanation:
The Enterobacteriaceae family is characterized by certain traits, such as being gram-negative rods, glucose fermenters, often being motile with peritrichous flagella, and sometimes being lactose fermenters. All the options provided are generally representative of the Enterobacteriaceae family except the gram-positive bacteria which are not members of this family. In contrast, the Enterobacteriaceae are gram-negative bacteria. Therefore, the correct answer is (a) gram-positive bacteria are not members of the Enterobacteriaceae family.