Final answer:
For administering ear drops to the right ear of an 18 month old, the correct position is lying on the back with the head turned to the left side, ensuring the medication properly flows into the ear canal. The option (2) is the correct option.
Step-by-step explanation:
When administering ear drops to an 18 month old patient for the right ear, the medical assistant should place the patient in position 2) Lying on the back with the head turned to the left side. This position allows the ear drops to flow down into the ear canal by gravity. It is important to administer medication correctly, especially in treating conditions like acute otitis media (AOM), which is a common ear infection in young children that can lead to the accumulation of fluid in the middle ear, known as otitis media with effusion (OME).