Explanation:

- Section 139: This section deals with the power of cross-examining witnesses who produce a document, but it doesn't relate to leading questions.

- Section 145: This section pertains to cross-examining a witness about their prior statements and doesn't address leading questions.

- Section 140: It concerns cross-examination of witnesses to test their veracity, not the rules for leading questions.

- Section 142: This section deals specifically with when leading questions may not be asked. It states that leading questions shall not be used in examination-in-chief, except with the permission of the court.