Statement 1 is Correct: The primary goal of stealth technology is to minimize an object's Radar Cross-Section (RCS), making it appear as small as a bird or insect on enemy screens. This is achieved through geometric shaping (to deflect waves away from the source) and by coating the surface with Radar Absorbing Materials (RAM), which absorb electromagnetic radar energy and dissipate it as heat.

Statement 2 is Correct: Stealth objects are not completely invisible. Their shapes and RAM coatings are typically optimized to defeat high-frequency radars (like X-band) used for precise weapons targeting. However, they can often be detected by low-frequency radars (such as VHF and UHF bands). The longer wavelengths of these specific frequencies resonate with the aircraft's physical dimensions, allowing detection, though they lack the resolution required for a missile lock.

Statement 3 is Incorrect: Metamaterials are artificially engineered structures with unique electromagnetic properties. In advanced stealth applications, they are used to decrease or eliminate radar scattering, not increase it. They achieve this by either perfectly absorbing the electromagnetic radiation or by bending and redirecting the waves smoothly around the object (electromagnetic cloaking) so that no signal scatters back to the radar receiver. Increasing scattering would make the object highly visible, defeating the purpose of stealth.

Therefore, the correct option is C.