What method involves the insertion of an implant using an incision in the arm and can remain effective for up to five years?

The method that involves the insertion of an implant using an incision in the arm and can provide effective contraception for up to five years is Norplant. Norplant consists of small, flexible rods that are placed under the skin of the upper arm, releasing hormones that prevent ovulation and thus effectively preventing pregnancy. This method is highly reliable and offers long-term contraceptive solutions compared to other methods that may require more frequent attention or administration.

In contrast, the other options do not match this description: the NuvaRing is a flexible ring worn in the vagina that releases hormones, the patch is a transdermal patch applied to the skin, and the diaphragm is a barrier method that requires insertion into the vagina but does not involve an implantable device in the arm. As such, Norplant stands out as the only choice consistent with the described method of implant use and duration of effectiveness.