What type of bundle is a bundle containing 5 pieces for zip code 64106 and 5 pieces for zip code 64107?

The correct choice identifies a 3-digit bundle. A 3-digit bundle refers to a grouping of mail pieces destined for different ZIP codes that share the same first three digits. In this case, the pieces going to zip code 64106 and 64107 both begin with the same prefix "641," which qualifies them as belonging to the same 3-digit grouping.

This type of bundling is beneficial for mail processing and delivery, as it allows for efficient sorting and delivery by carriers who can handle multiple routes or addresses that fall within the specified range. Thus, since both ZIP codes fall under the same 3-digit classification, the answer reinforces the principles of mail sorting and bundling in a postal context.