"what type of index has an index key value that points to a data row, which contains the key value? "

The nonclustered index is a type of index that has an index key value that points to a data row, which contains the key value.
This index has a structure separate from the data rows and contains index key values and each key value entry has a pointer to the data row that contains the key value.
Clustered indexes on the other hand sort and store the data rows in the table or view based on their key values.