A finds the key to Y's house door, which Y had lost, and commits house-trespass by entering Y's house having opened the door with that key. What offence has A committed?

Option (1) is incorrect: Lurking house-trespass is whoever commits house-trespass having taken precautions to conceal such house-trespass from some person who has a right to exclude or eject the trespasser from the building, tent or vessel. Option (2) is incorrect: Criminal misappropriation is whoever dishonestly misappropriates or converts to his own use any movable property. Option (3) is incorrect: Whoever attempts to commit an offence of theft or to cause such an offence to be committed, and in such attempt does any act towards the commission of the offence, shall be liable for attempt to commit theft. Option (4) is correct: A person is said to commit 'house-breaking' who commits house-trespass if he enters or quits by opening any lock in order to the committing of the house-trespass, or in order to the quitting of the house after a house-trespass.