Step 1: Rule out the unrelated seed-quality terms.
Seed priming is a controlled hydration treatment used to speed up and synchronise germination, it has nothing to do with pest protection. Seed conditioning refers to cleaning, grading and upgrading a seed lot by removing debris and off-size seed, again a quality operation rather than a chemical protection step. Seed seasoning is not a defined technical term in seed technology, so it can be discarded outright.
Step 2: Define the process the question actually describes.
Coating a seed with a fungicide or insecticide, as a dust, slurry or liquid film, before or at the time of sowing so that the emerging seed and seedling are shielded from soil-borne fungi and soil insects, is precisely what is called seed dressing in agricultural science.
Step 3: Match the definition to the question.
The question describes exactly this protective chemical coating applied for defence against fungal and insect attack after planting, which matches the definition of seed dressing and none of the other three terms.
\[ \boxed{Seed dressing} \]