Regular Expression vs Delimiter Rule

Using the classification rule builder, an analyst needs to create a classification report for marketing tracking codes by the campaign name value codes. Below is an example of several tracking codes, where the item between the underscores represents the campaign name:

1. paid-search_non-branded-phrases_jeans

2. social-media_brand-awareness_twitter

3. display-advertising_brand-awareness_media-site

4. affiliates_shipping-discounts_affiliate-network

What kind of classification rule should the analyst create?

A. A Regular Expression rule that matches the pattern of the 2 underscores, pulling out the value between them

B. A Delimiter rule that breaks the tracking code apart at the underscore, placing the second item in the classification