**Core Concept**
Gamma radiation is a form of ionizing radiation that is emitted by certain radioactive isotopes, including Iridium-192 (Ir-192). Gamma radiation has a high energy level and can penetrate deep into tissues, making it useful for diagnostic and therapeutic applications in medicine.

**Why the Correct Answer is Right**
Ir-192 is a radioactive isotope that decays through beta and gamma emission. The gamma radiation emitted by Ir-192 has an energy level of approximately 300-400 keV, which is suitable for use in radiation therapy and industrial applications. The gamma radiation is produced through the decay of the excited nucleus of Ir-192, which releases energy in the form of electromagnetic waves.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided, so we will proceed to the remaining options.
* **Option B:** This option is not correct because Ir-192 is known to emit gamma radiation, but it's not the only radioactive isotope that does so. Other isotopes like Co-60 and Cs-137 also emit gamma radiation.
* **Option C:** This option is not correct because Ir-192 emits gamma radiation, but it's not the primary form of radiation emitted by this isotope. Beta radiation is also emitted, but it's not as energetic as gamma radiation.
* **Option D:** This option is not correct because Ir-192 is a radioactive isotope that emits gamma radiation, but it's not a neutron source.

**Clinical Pearl / High-Yield Fact**
When working with radioactive isotopes like Ir-192, it's essential to follow strict safety protocols to prevent radiation exposure. This includes using lead shielding, wearing personal protective equipment, and following proper handling and storage procedures.

**Correct Answer: B. Gamma radiation.**