Final answer:
The reference column is the first column of the lookup table that contains the data you are comparing to your "lookup_value".
Step-by-step explanation:
In the context of Excel and data lookup functions, the first column of the lookup table that contains the data you are comparing to your "lookup_value" is called the Reference column (option B).
The reference column is the column you want to search in for a specific value. It is the column that the lookup function will use to find a match for your lookup value.
For example, if you have a table with student names in the first column and their corresponding grades in the second column, the first column (containing the names) would be the reference column.