Enumerations can contain values.
a. only unique
b. an indefinite number of
c. up to 10
d. up to 100

(A) Only unique

Explanation:

 Enumeration basically contain only unique value as enumeration is define as the set of the numeric values that is finite and it is represent specifically by the identifiers which is known as the enumeration constant.  

It only work with the finite values and also hide all the un-relevant and unnecessary information from the programmers. Enumeration is the type of the data type variable which contain only previous declared values.  

d. local area network (lan)

explanation:

a local area network (lan) is a collection of computers it connected to one another or to a common connection medium.

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