In the context of intention to create legal relations, what is the legal presumption regarding commercial agreements?

There is a presumption against legal relations unless the agreement is in writing.

There is a strong presumption that the parties intended to create legal relations, which can only be rebutted by clear evidence.

There is no presumption; intention must be proven by the claimant in all cases.

Commercial agreements are only binding if they contain a 'subject to contract' clause.