Explanation:

- Option 1: Take an interest

- This means acquiring a stake or share in something. In the context of mortgages, it's not the primary intention of depositing title deeds.

- Option 2: Take a possession

- Taking possession suggests gaining physical control or ownership. Equitable mortgage relies on security rather than possession.

- Option 3: Create a security

- This is the correct option. The intention to deposit title deeds in an equitable mortgage is primarily to create a security interest in the property.

- Option 4: Take a consideration

- Consideration involves something of value, like money, given in return for a service or property. Not the main purpose of title deed deposit in this context.