"Too young" seems irrelevant, because all seedlings start with their first day.

There are like 16 essential plant elements, where a plant must have every one of the 16. Those are 16 essential nutrients.

Based on the question's vacabulary, "sunlight" is not neccessary, because artificial light with substitute. So "sunlight" is not essential.

The only right answer I can see, is "b" which is "lacked nutrients.

Cheers,

M. D. Vaden

To add, some seedlings are susceptible to disease, but old plants and trees get disease too. So the "young" part still seems like an odd component for the answer in this context.

What a poorly written question! Amazing what passes as "teaching" in some schools these days.

I agree with the above posts - "B" is the only viable
answer given the wording of the other answers.