Which of the following shows the nomenclatures for IR illuminating rounds?

The correct answer, indicating the nomenclatures for IR illuminating rounds, is supported by the fact that the M1066 and M1123 rounds are specifically designed for illumination purposes in various conditions, including night operations.

The M1066 is a 105mm illuminating round, while the M1123 is a 155mm illuminating round, both serving the essential function of providing illumination to enhance visibility for ground troops and aid in targeting. These rounds utilize infrared capabilities, making them particularly effective in low-light scenarios, thus their designation as IR illuminating rounds.

Other choices include rounds that serve different functions; for instance, the M982 is a precision-guided projectile, while the M495 is a type of high-explosive round. The M110 and M107 are historical artillery rounds, with the M110 being a 203mm howitzer round and the M107 being a standard high-explosive 155mm round. Lastly, the M795 and M549 are also conventional munitions used for explosive purposes rather than illumination.