I didn't read the book but i checked this other site and it said c.Scream(NotSure)
Answer:
Instruction.
Explanation:
A tunic can be defined as a type of garment that is usually sleeveless and it is worn reaching the knees. Tunics were typically worn by ancient Greeks and Romans.
A recipe can be defined as any series of instructions that guides people on how to prepare or make things such as food, cake, paint, etc. Therefore, a recipe is a list of step-by-step instructions that should be to prepare something.
Hence, a tunic is to garment as recipe is to instruction.
That would be the Chloroplast
It was uncommon that a bright student would have such poor grades.