In terms of the data relationships found by data mining, sequences refers to:
a. events linked over time.
b. patterns that describe a group to which an item belongs.
c. occurrences linked to a single event.
d. classifications when no groups have yet been defined.
e. undiscovered groupings.

Option (C)

Explanation:

Relational data mining is referred to as or known as data mining method or technique used for the relational databases. It acts unlike the algorithms of traditional data mining, that tend to look for the  propositional patterns in single table, algorithms of relational data mining tends to look for the relational patterns among the multiple tables.

the answer is d.index

answer; aristotle;