Which of the following actions would classify as " burglary" under Missouri law?

The action that classifies as "burglary" under Missouri law is entering a private residence unlawfully with the intent to commit theft. In Missouri, burglary is defined as knowingly entering or remaining unlawfully in a building or inhabitable structure with the intent to commit a crime therein, which can include theft.

In this scenario, the critical elements are the unlawful entry and the intent to commit a crime upon entry. Entering a private residence without permission clearly fulfills the unlawful entry condition, and if the intent is to steal, this directly aligns with the legal definition of burglary.

The other options do not meet the necessary criteria for burglary. Entering a store during business hours is typically lawful if the individual has no intent to commit a crime. Walking into a friend's house without knocking might not constitute unlawful entry if there is implicit permission. Taking someone's bicycle while they aren't looking may indicate theft, but it does not involve unlawful entry into a structure, which is essential for a burglary charge. Thus, the correct answer focuses on the clear elements of unlawful entry and criminal intent characteristic of burglary under Missouri law.