What crime might a shopper be arrested for if they are caught stealing merchandise after admitting they entered the store with the intention to steal?

In this scenario, the correct answer is burglary. Under California law, burglary is defined as the act of entering a structure with the intent to commit a crime inside, which includes theft among other offenses. Since the shopper admitted they entered the store with the intention to steal, they fulfill the requirements of burglary by having that intent at the moment of entry.

Shoplifting specifically involves the unlawful taking of merchandise with the intent to permanently deprive the owner of it, but it doesn't encompass the aspect of entering with intent to commit a crime. Theft is a broad term that refers to taking someone else's property unlawfully, but without the aspect of entering with the intent to commit a crime, it does not capture the full scenario as described here. Robbery involves taking property from a person through force or intimidation, which does not apply in this situation, as the shopper's actions do not involve any direct confrontation or force against another person.

Thus, the most accurate classification of the shopper's actions, given their admission and circumstances, is burglary.