This answer is unsupported. We know for a fact that the core contains tellurium, and there's no other reason to think that material ejected directly from the core would not contain tellurium.

This answer is strongly supported. All three isotopes found are easily dissolved by steam, all three are found in the plant’s core, and steam may have been in contact with the core. So, the material was likely carried into the atmosphere by steam. This also explains why heavy isotopes, which would have been ejected directly from the core, were not found.

This answer is unsupported. We don’t know from the stimulus whether the spent fuel rods were damaged or not. We can only infer that the material found did not come from spent fuel rods.

This answer is anti-supported. We know from the stimulus that material ejected directly from the core would include heavy isotopes, yet the researchers did not find any heavy isotopes.

This answer is unsupported. We don’t know from the stimulus whether spent fuel rods do not contain heavy isotopes. We only know that spent fuel rods do not contain significant amounts of tellurium.