Final answer:
The JTR reference that allows reimbursement for interpreter services with the AO's authorization is JTR Chapter 4.
Step-by-step explanation:
The Joint Travel Regulations (JTR) reference that allows travelers to receive reimbursement for interpreter services with the Authorization Officer's (AO) authorization/approval is found in JTR Chapter 4. This chapter typically covers the provisions related to travel and associated expenses, including special or uncommon expenses such as the need for an interpreter during official travel. Travellers should ensure they have prior authorization from their AO to avoid any issues with reimbursement. The inclusion of interpreter services in Chapter 4 suggests that the regulations provide detailed information on how individuals, who are authorized and approved by the Authorizing Official (AO), can seek reimbursement for interpreter services incurred during travel.