Which type of service would most likely utilize a code beginning with "J"?

Codes that begin with "J" in the HCPCS Level II coding system are specifically designated for pharmaceuticals that are typically administered via injection. This includes a variety of medications such as biologics, infusions, and other injectable drugs.

Medications administered via injection often require specific coding to identify them correctly for billing and reimbursement purposes. The HCPCS codes starting with "J" provide a standardized way to represent these drugs, which is critical for healthcare providers and payers to ensure accurate reporting and payment for services rendered.

In contrast, the other options involve different types of services that do not typically fall under the "J" code category. Inpatient rehabilitation services, personal care services, and physical therapy services do not primarily focus on injectable medications and instead involve therapy and support services that would be identified with different classifications of codes. Thus, the choice that aligns with "J" codes is indeed the administration of medications via injection.