How can you summarize data using the SUMIF function?

The SUMIF function in spreadsheet applications is designed for conditional summation, which makes option B the correct explanation of how to summarize data using this function. Specifically, the SUMIF function allows you to specify a range to evaluate, a set of criteria to determine which values to include, and an additional range that contains the actual values to be summed.

For example, if you want to sum sales data only for a specific product, you would use the range to check the product names, set the criteria to that particular product name, and provide the range of sales figures that correspond to those names. This powerful function thus enables targeted data analysis by allowing users to sum only the values that meet certain conditions, improving efficiency and insight into the data.

The other options do not align with the functionalities of the SUMIF function. Counting entries (first option) refers to the COUNT function, averaging values (third option) pertains to the AVERAGE function, and filtering for unique values (fourth option) would involve functions like UNIQUE or advanced filtering techniques rather than summation.