Explanation:

- Option 1: Theft

- Theft involves taking someone's property with intent to permanently deprive them of it.

- This scenario doesn't fit as no property is moved or taken.

- Option 2: Criminal breach of trust

- This involves someone entrusted with property using it against the express terms of trust.

- There is no trust relationship described here.

- Option 3: Cheating

- Cheating involves deception to fraudulent ends or gaining a wrongly obtained advantage.

- Here, threat or inducement is used more than deception.

- Option 4: Extortion

- Extortion involves putting someone in fear of injury to obtain consent to deliver property or valuables.

- A induces fear of grievous hurt to get Z to sign a blank paper, fitting extortion's definition.

Option 4: Extortion