Which of the following acts constitute the commissioning of theft?

The act that constitutes the commissioning of theft among the given options is: C finds a necklace in the bedroom of D and retains the necklace.

• Actus reus: In this case, C has taken control of the necklace belonging to D without their consent, fulfilling the actus reus (guilty act) element of theft.
• Mens rea: Since C found the necklace in D's bedroom, they knew or ought to have known that it belonged to someone else. This satisfies the mens rea (guilty mind) element of theft, which requires knowledge and intention to deprive the rightful owner of their property.