What does the term "clear signs" (bayyināt) refer to in this āyah?

Imām Ibn al-Jawzī (d. 597/1201) summarized the scholars' opinions in his book "Zād al-Masīr" as follows:

1. It refers to what was written in the tablets concerning what is lawful and unlawful. [Ibn ʿAbbās]
2. It refers to the nine signs (See 17:101). [Muqātil]