Passage Summary: After a nuclear accident, specific chemicals were found in the air, but heavy ones were missing. These chemicals come from either the fuel rods or the core. We know the fuel rods don't have tellurium, and we know a direct core blast would have released heavy stuff. However, steam was released, and it can carry the specific chemicals found.

Reasoning: The isotopes found (iodine, tellurium, cesium) are present in the core and soluble in steam, but the absence of heavy isotopes suggests the material was not ejected directly from the core; furthermore, tellurium is not found in spent fuel rods.

Analysis: In a 'Most Strongly Supported' task, we act like detectives combining clues. We know the material didn't come from the spent fuel because tellurium was present. We know it likely wasn't a direct 'ejection' from the core because the heavy isotopes were missing. However, we are told that steam contacted the core and that the core contains the three isotopes found, which are 'easily dissolved' by steam. The most logical synthesis is that the radioactive material was carried out of the core by the steam, rather than being blown out directly or coming from the fuel rods.