Final answer:
The oval radiolucency between the root of tooth #9 on a radiograph is the Incisive foramen, which is the oral opening of the nasopalatine canal.
Step-by-step explanation:
The normal radiographic landmark seen as an oval radiolucency between the root of tooth #9 is the Incisive foramen. This structure is located in the anterior maxilla just posterior to the central incisors. It is the oral opening of the nasopalatine canal and it is where the nasopalatine nerve and vessels pass. The nasopalatine duct mentioned in option B is essentially another term for the same canal. Accordingly, the correct answer is A) Incisive foramen.